Gastrointestinal

Colon polyps: tissue, complete removal and follow-up

Distinguish adenomas and serrated lesions, check examination and resection quality, and choose follow-up from pathology, polyp burden and prior findings.

A polyp has been removed. Is the next task to inspect its scar, survey the rest of the colon, or assess an invasive cancer? Start with that distinction before choosing a date.

This lesson uses the 2020 US Multi-Society Task Force surveillance framework, with the 2025 bowel-preparation update. The ordinary intervals assume complete removal during a high-quality examination in an otherwise average-risk adult. Hereditary syndromes, inflammatory bowel disease, prior colorectal cancer, malignant polyps and relevant family history require their own assessment. These are educational examples, not individual treatment instructions. [1] [5]

Does advanced mean invasive?

A 14 mm tubulovillous adenoma contains high-grade dysplasia. Its intact specimen has clear margins and no submucosal invasion. The alarming words do not, by themselves, establish a cancer requiring colectomy.

Advanced adenoma means an adenoma measuring at least 10 mm, containing villous or tubulovillous architecture, or containing high-grade dysplasia, without invasive colorectal cancer. Any one feature is sufficient. Low-grade dysplasia is part of an ordinary conventional adenoma; it is not the high-grade criterion. Size and architecture describe risk, while invasion describes depth. [1]

The upper model keeps dysplasia above the muscularis mucosae. In the lower model, malignant glands cross the muscle band into submucosa. Simplified original educational drawing. — Trace the muscularis mucosae before classifying depth. This original simplified model is not a pathology specimen. [3]

Your task: locate the boundary in the drawing. Then decide which new finding would change the problem from post-polypectomy surveillance to malignant-polyp management: more villous tissue, or confirmed submucosal invasion?

Invasive colorectal carcinoma in a malignant polyp extends through the muscularis mucosae into the submucosa. High-grade dysplasia confined to the mucosa has not crossed that boundary. Confirmed submucosal invasion prompts assessment of margin clearance, depth, differentiation, lymphovascular invasion and other adverse features; it does not automatically mean every patient needs the same operation. [3]

For the opening specimen, confident complete removal and a high-quality examination permit a 3-year surveillance recommendation. Three advanced features do not add up to a mandatory 1-year interval. [1]

Transfer: a completely removed 7 mm villous adenoma can still enter the US 3-year group. A 7 mm tubular adenoma with only low-grade dysplasia does not enter that group because of dysplasia alone. Identify which feature, rather than which adjective, changes the decision.

Try a question on this topic

A 74-year-old man is in the hospital after admission 4 days ago for decompensated heart failure. Two days ago he had an episode of hypotension to 78/44 mm Hg that required a norepinephrine infusion for 10 hours. This morning he developed sudden crampy pain in the left abdomen, followed within several hours by an urge to defecate and passage of bright red blood mixed with stool. He has hypertension and coronary artery disease and takes furosemide, carvedilol, and aspirin. Temperature is 37.8°C (100.0°F), pulse is 98/min, and blood pressure is 108/64 mm Hg. There is mild tenderness in the left upper and lower quadrants without guarding. Serum lactate is 2.6 mmol/L. Colonoscopy shows edematous, friable mucosa with patchy ulcers confined to the distal transverse colon and the splenic flexure, with normal rectum. Biopsy specimens show mucosal necrosis, shrunken crypts, and a hyalinized lamina propria.

Which of the following best explains where the damage occurred?

Choose an answer before revealing the reasoning.

Get one of these every morning · Practice more in the QBank

Was the colon adequately examined and cleared?

Two reports describe a single 6 mm tubular adenoma. One documents a clean examination to the cecum and complete excision. The other says adherent stool prevented assessment of substantial mucosa even after washing. Identical pathology does not make these equivalent examinations.

Before assigning an interval, confirm completion to the cecum, preparation adequate to detect lesions larger than 5 mm, careful inspection and confidence that visible lesions were completely removed. Record each lesion's location, size in millimeters, morphology, retrieval and pathology. A photograph beside an instrument of known size helps substantiate a management-changing measurement. [1] [2]

Examination quality → removal quality → pathology and burden → follow-up plan. This is a reasoning order, not permission to postpone treatment of a concerning lesion.

Your task: identify the missing prerequisite in the second report before consulting an interval table.

The missing prerequisite is reliable inspection. If preparation is inadequate for assigning standard screening or surveillance intervals, the 2025 guidance recommends completing colonoscopy within 12 months, with a revised preparation strategy. After an abnormal noncolonoscopic screening test, repeat as soon as possible, usually within 3 months. Alarm symptoms can require earlier diagnostic assessment. Merely reaching the cecum does not establish adequate preparation. [5]

Removal quality is a separate question. A large nonpedunculated lesion without signs of deep invasion may be suitable for advanced endoscopic resection. Refer a technically difficult benign-appearing lesion to an experienced resection endoscopist rather than choosing surgery solely because it is large. Conversely, a depressed area with disrupted surface and vascular patterns suspicious for deep invasion needs the appropriate malignant-lesion pathway, not indiscriminate piecemeal removal. [2] [3]

Transfer: an excellent preparation does not compensate for known residual adenoma. Arrange completion of treatment and individualized reassessment rather than applying a routine interval to an incompletely treated lesion. Likewise, an old surveillance date is not a reason to defer evaluation of new symptoms. [1] [2]

Read the tissue before naming the pathway

All five lesion families below can be called polyps at endoscopy. That gross description does not determine whether they share a cancer pathway or a surveillance interval.

Conventional adenomas contain dysplastic epithelium. Tubular architecture is predominantly gland-forming; villous architecture has elongated projections with supporting cores; tubulovillous adenomas combine both. A villous contour alone is not sufficient to classify a serrated lesion as a conventional villous adenoma. Traditional serrated adenomas can also have a villiform outline. [1] [4]

Elongated branching projections demonstrate villous architecture, without establishing the entire lesion margin or invasion depth. — Find a long projection and follow its supporting core. This field demonstrates architecture, not a complete assessment of invasion or margins.
Image: Nephron, original photograph, CC BY-SA 3.0. Source [8].

For serrated lesions, examine the crypt base. A typical hyperplastic polyp has relatively straight, symmetric crypts with serration more prominent toward the surface. A sessile serrated lesion, abbreviated SSL, shows abnormal basal architecture such as dilation, branching and horizontal growth. An SSL can be a precursor without the conventional nuclear dysplasia expected in a tubular adenoma. [4]

A relatively straight hyperplastic crypt is compared with a distorted sessile serrated lesion crypt that has basal dilation, deep serration and horizontal growth. — Compare the lower part, not just the sawtooth surface. The drawing isolates architecture; real tissue varies with section orientation. [4]

Compare serration and expanded basal crypt architecture in an actual low-power tissue field; classify the lesion from the complete specimen. — Trace a dilated basal crypt in the upper tissue strip. Use the complete specimen and pathology report to classify a lesion.
Image: Nephron, original photograph, CC BY-SA 3.0. Source [9].

Your task: compare the two photographs. Explain why finger-like projections and distorted crypt bases answer different questions rather than treating both as simply an irregular polyp.

An SSL commonly participates in a BRAF-associated, CpG-island methylation pathway. Later MLH1 promoter methylation can impair mismatch repair and produce microsatellite instability. This is a biologic pattern, not a genotype inferred from location alone, and not proof of an inherited syndrome. Traditional serrated adenomas have characteristic serrated architecture, often eosinophilic cells and ectopic crypt formation; molecular findings are more heterogeneous. [4]

Transfer: if a 6 mm SSL acquires dysplasia, its small size no longer keeps it in the low-risk small-SSL group. A completely excised traditional serrated adenoma also warrants 3-year US surveillance even when it is small. Do not transfer the 1-to-2 small tubular-adenoma rule to either lesion. [1]

Use location and count without confusing them

A mucus-capped flat lesion in the proximal colon should make an endoscopist inspect carefully for a serrated lesion. Small hyperplastic polyps commonly occur in the rectosigmoid. These tendencies guide attention; neither location nor a mucus cap replaces histology. Washing can expose subtle margins but also make a pale lesion harder to see. [4]

A proximal lesion reported as hyperplastic deserves clinicopathologic review when the specimen is poorly oriented or the local distinction from SSL is uncertain. A confidently classified small proximal hyperplastic polyp is not automatically an SSL. Size at least 10 mm, however, prevents use of the small-hyperplastic-polyp rule. [1]

A specimen ledger from one complete examination
Region	Pathology
Ascending colon	One 5 mm tubular adenoma
Descending colon	One 7 mm tubular adenoma
Rectum	Three 3 mm hyperplastic polyps

Your task: count the conventional adenomas, then count all removed polyps. Why should those totals differ?

There are two conventional adenomas but five polyps. If the adenomas have only low-grade dysplasia and removal was complete, the three tiny rectal hyperplastic polyps do not turn this into the five-adenoma category. This otherwise average-risk patient fits the 7-to-10-year group. The whole colon matters, but each histologic family must be counted correctly. [1]

Keep a second ledger across examinations. More than 10 adenomas at a single high-quality examination supports 1-year surveillance. More than 10 over a lifetime can justify genetic assessment, interpreted with age, family history and phenotype; it is not the same numeric instruction for the next colonoscopy. A polyposis phenotype is not proof of a particular gene. [1]

Serrated polyposis also uses cumulative counts. WHO 2019 criteria include either at least five serrated lesions proximal to the rectum, all at least 5 mm and at least two at least 10 mm, or more than 20 serrated lesions throughout the large bowel, including at least five proximal to the rectum. Count all serrated histologic subtypes. Meeting either criterion requires a specialist polyposis pathway, not the ordinary small-polyp table. [6]

Transfer: three qualifying proximal serrated lesions today can complete a syndrome-defining count when three others were documented previously. Reconstruct the history before reassuring someone from today's count alone.

Change the resection, change the first follow-up

Imagine one 20 mm adenoma in an otherwise average-risk adult. The colon is adequately examined and the specimen has no invasive cancer. First picture an intact, confidently complete excision. Then change only the removal method to piecemeal.

A specimen-and-scar experiment

Predict which information becomes harder to establish when one specimen becomes several. Use the two optional controls to add the changed specimen and then inspect its scar. Close them to reset; the explanation below remains available throughout.

A specimen diagram has a continuous outer contour. The example assumes confident complete excision of a noninvasive 20 mm adenoma during a high-quality examination, supporting routine three-year surveillance. — Starting condition: an intact, confidently complete 20 mm adenoma excision. The drawing represents specimen continuity, not histologic proof of a clear margin. [1] [2]

Show the effect of dividing the specimen

The original 20 mm lesion is represented as four separated specimen pieces. Solid contours denote original outer edges and dashed lines denote newly created cut edges. Fragmentation does not create four separate polyps or four complete original margins. — The size and diagnosis stay fixed. Fragmentation disrupts reconstruction of the original boundary; local residual tissue becomes an important follow-up concern.

The extra cut edges are not four new outer margins. A visually complete piecemeal removal can still leave microscopic or inconspicuous tissue at the site.

Inspect the six-month scar result

Two views of mucosa compare a clear scar with a small residual adenoma nodule. The comparison distinguishes an eradication target from a clear site; the surrounding colon still requires examination. — A residual nodule calls for treatment and further assessment. A clear scar permits the planned surveillance sequence; neither finding eliminates examination of the remaining colon.

A benign residual adenoma is not automatically an invasive cancer. Treat identified residual or recurrent tissue and reassess eradication with the appropriate endoscopist.

What changed? Confidently complete intact excision of this noninvasive advanced adenoma supports the ordinary 3-year interval. Piecemeal resection of an adenoma or SSL at least 20 mm instead requires a first colonoscopy at about 6 months. Exactly 20 mm is included. That early examination particularly checks the resection site for residual or recurrent tissue, while still examining the colon. It is not a prediction that the polyp will become cancer in six months. [1] [2]

After the first early examination, the recommended large-piecemeal sequence is another colonoscopy 1 year later, then 3 years after the second surveillance, adjusted for findings. Residual tissue requires treatment and an individualized eradication plan rather than automatic advancement along that schedule. [2]

Transfer: known incomplete removal of an 18 mm lesion also needs completion of treatment. Being below the 20 mm threshold does not make residual tissue safe to ignore, and the 6-month rule should not be assigned mechanically to every smaller piecemeal lesion.

Choose an interval from the complete profile

Use these as first-surveillance recommendations after complete removal at a high-quality examination, unless a row describes the special piecemeal pathway. They are not a substitute for clearing residual tissue or resolving an inadequate examination. A range is a recommended range, not a mandate to choose its earliest endpoint.

Conventional adenomas: USMSTF 2020 [1]
Finding	Next colonoscopy
1 or 2 tubular adenomas, each under 10 mm, low-grade dysplasia only	7 to 10 years
3 or 4 such adenomas	3 to 5 years
5 to 10 such adenomas	3 years
Any adenoma at least 10 mm, villous or tubulovillous histology, or high-grade dysplasia	3 years
More than 10 adenomas at one examination	1 year; assess possible hereditary disease
Adenoma at least 20 mm resected piecemeal	6 months initially

Serrated findings: USMSTF 2020 [1]
Finding	Next examination
Up to 20 hyperplastic polyps under 10 mm in rectum/sigmoid	10 years
Up to 20 hyperplastic polyps under 10 mm proximal to sigmoid, confidently classified	10 years; weaker evidence
Hyperplastic polyp at least 10 mm	3 to 5 years
1 or 2 SSLs under 10 mm without dysplasia	5 to 10 years
3 or 4 such SSLs	3 to 5 years
5 to 10 such SSLs, an SSL at least 10 mm, or an SSL with dysplasia	3 years
Traditional serrated adenoma	3 years
SSL at least 20 mm resected piecemeal	6 months initially

A normal high-quality examination in an average-risk adult supports repeat screening in 10 years. For a hyperplastic polyp at least 10 mm, favor 3 rather than 5 years when there are concerns about distinguishing HP from SSL, preparation quality or complete excision. Actual inadequate preparation or known residual tissue needs the separate corrective pathway, not simply a shorter routine interval. [1] [5]

Your task: compare a completely excised 11 mm villous adenoma with four completely excised nondysplastic 4 to 7 mm SSLs. The former supports 3 years; the latter supports a 3-to-5-year range. Changing histologic family changes which row you consult.

For mixed findings, integrate every lesion and relevant history, favoring the shortest applicable recommendation without simply adding adenoma and SSL counts into an invented combined category. Some mixed profiles have limited direct evidence. Document the reason for the chosen plan. Evidence is particularly limited for several serrated recommendations; equal-looking numbers do not imply equal certainty. [1]

Prior findings also matter at later surveillance. After an advanced adenoma followed by a normal first surveillance, the US table recommends the next examination in 5 years. After 1 or 2 small tubular adenomas followed by a normal first surveillance, the next interval is 10 years. Do not erase the baseline history when reading a reassuring new report. [1]

A separate family-history rule can be shorter than the polyp interval. For example, ACG recommends 5-year colonoscopy when a first-degree relative had colorectal cancer before age 60, in the relevant nonsyndromic setting. New bleeding, unexplained iron-deficiency anemia or other alarm findings require diagnostic assessment rather than waiting for a surveillance date. [10] [11]

Transfer: explain both the date and its purpose in the patient letter: clearing a prior uncertainty, inspecting a resection site, or surveilling future neoplasia. State the examination quality, relevant pathology and prior history supporting it. This lesson uses US recommendations; ESGE 2020 does not shorten follow-up solely for villous architecture in 1 to 4 small low-grade adenomas. Do not combine rules from different frameworks. [7]

Apply the tissue, quality and follow-up distinctions

These original educational cases use the stated US framework unless another source is named. Read the clinical question before viewing its options. Each choice has specific feedback; returning to the teaching does not require completing the bank.

Case 1

Show answer and explanations

A. Invasive carcinoma; referral for staging (Why this does not fit)
Confirmed submucosal invasion would require malignant-polyp assessment. The specimen explicitly lacks submucosal invasion. Classify invasion by tissue depth rather than dysplasia grade alone.
Reasoning steps for option A
1. Which invasion-depth finding would make 'Invasive carcinoma; referral for staging' appropriate in polyp-01?
  Confirmed submucosal invasion would require malignant-polyp assessment.
2. Which invasion-depth finding in polyp-01 argues against 'Invasive carcinoma; referral for staging'?
  The specimen explicitly lacks submucosal invasion.
3. Which invasion-depth distinction from polyp-01 should guide a similar decision about 'Invasive carcinoma; referral for staging'?
  Classify invasion by tissue depth rather than dysplasia grade alone.
B. Low-risk adenoma; colonoscopy in 7 to 10 years (Why this does not fit)
One or two small tubular adenomas with low-grade dysplasia fit this range. This lesion is 14 mm, tubulovillous and high-grade. Complete removal does not erase advanced histologic or size features.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make 'Low-risk adenoma; colonoscopy in 7 to 10 years' appropriate in polyp-01?
  One or two small tubular adenomas with low-grade dysplasia fit this range.
2. Which size-threshold finding in polyp-01 argues against 'Low-risk adenoma; colonoscopy in 7 to 10 years'?
  This lesion is 14 mm, tubulovillous and high-grade.
3. Which resection-method or completeness distinction from polyp-01 should guide a similar decision about 'Low-risk adenoma; colonoscopy in 7 to 10 years'?
  Complete removal does not erase advanced histologic or size features.
C. Advanced adenoma; colonoscopy in 3 years (Best answer)
The reported dysplasia has not invaded the submucosa. Size, villous architecture and high-grade dysplasia each support the advanced-adenoma category after complete excision. Advanced adenoma risk supports surveillance, not colectomy solely for the adjective advanced.
Reasoning steps for option C
1. Has the reported dysplasia crossed into the submucosa?
  The reported dysplasia has not invaded the submucosa.
2. Which separate findings determine adenoma risk?
  Size, villous architecture and high-grade dysplasia each support the advanced-adenoma category after complete excision.
3. What follows from keeping risk and depth separate?
  Advanced adenoma risk supports surveillance, not colectomy solely for the adjective advanced.
D. Residual adenoma; colonoscopy in 6 months (Why this does not fit)
An early scar examination is appropriate after large piecemeal resection. This lesion was excised intact with clear margins, and residual tissue is not described. Do not substitute a residual-tissue pathway for routine surveillance after confident complete excision.
Reasoning steps for option D
1. Which resection-method or completeness finding would make 'Residual adenoma; colonoscopy in 6 months' appropriate in polyp-01?
  An early scar examination is appropriate after large piecemeal resection.
2. Which resection-method or completeness finding in polyp-01 argues against 'Residual adenoma; colonoscopy in 6 months'?
  This lesion was excised intact with clear margins, and residual tissue is not described.
3. Which resection-method or completeness distinction from polyp-01 should guide a similar decision about 'Residual adenoma; colonoscopy in 6 months'?
  Do not substitute a residual-tissue pathway for routine surveillance after confident complete excision.

Takeaway: Advanced adenoma risk supports surveillance, not colectomy solely for the adjective advanced.

Case sources: [1] [3]

Case 2

Show answer and explanations

A. From 7 to 10 years to 3 years (Best answer)
Before correction, two sub-10 mm low-grade tubular adenomas fit the 7-to-10-year group. Exactly 10 mm meets the advanced-size threshold, supporting 3-year surveillance. An inclusive size boundary can change follow-up even when histology and count are unchanged.
Reasoning steps for option A
1. What category applied to the initial measurements?
  Before correction, two sub-10 mm low-grade tubular adenomas fit the 7-to-10-year group.
2. What changes when the larger diameter is exactly 10 mm?
  Exactly 10 mm meets the advanced-size threshold, supporting 3-year surveillance.
3. Which comparison should be preserved in a similar report correction?
  An inclusive size boundary can change follow-up even when histology and count are unchanged.
B. From 7 to 10 years to 6 months (Why this does not fit)
Six-month surveillance is used initially after piecemeal resection of an adenoma or SSL at least 20 mm. The corrected lesion is 10 mm and was completely removed, without that resection scenario. Do not confuse the advanced-size threshold with the large-piecemeal threshold.
Reasoning steps for option B
1. Which resection-method or completeness finding would make 'From 7 to 10 years to 6 months' appropriate in polyp-02?
  Six-month surveillance is used initially after piecemeal resection of an adenoma or SSL at least 20 mm.
2. Which resection-method or completeness finding in polyp-02 argues against 'From 7 to 10 years to 6 months'?
  The corrected lesion is 10 mm and was completely removed, without that resection scenario.
3. Which resection-method or completeness distinction from polyp-02 should guide a similar decision about 'From 7 to 10 years to 6 months'?
  Do not confuse the advanced-size threshold with the large-piecemeal threshold.
C. From 3 to 5 years to 3 years (Why this does not fit)
Three or four small tubular adenomas fit the 3-to-5-year group. There are two adenomas, so the proposed starting range is incorrect. Establish the starting category before predicting the effect of a changed measurement.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make 'From 3 to 5 years to 3 years' appropriate in polyp-02?
  Three or four small tubular adenomas fit the 3-to-5-year group.
2. Which adenoma count, size, or histology finding in polyp-02 argues against 'From 3 to 5 years to 3 years'?
  There are two adenomas, so the proposed starting range is incorrect.
3. Which case-specific distinction from polyp-02 should guide a similar decision about 'From 3 to 5 years to 3 years'?
  Establish the starting category before predicting the effect of a changed measurement.
D. From 7 to 10 years to 1 year (Why this does not fit)
More than 10 adenomas at one examination supports 1-year surveillance. A diameter of 10 mm is not a count of more than 10 adenomas. Keep dimensions and lesion counts in separate fields.
Reasoning steps for option D
1. Which adenoma count, size, or histology finding would make 'From 7 to 10 years to 1 year' appropriate in polyp-02?
  More than 10 adenomas at one examination supports 1-year surveillance.
2. Which adenoma count, size, or histology finding in polyp-02 argues against 'From 7 to 10 years to 1 year'?
  A diameter of 10 mm is not a count of more than 10 adenomas.
3. Which case-specific distinction from polyp-02 should guide a similar decision about 'From 7 to 10 years to 1 year'?
  Keep dimensions and lesion counts in separate fields.

Takeaway: An inclusive size boundary can change follow-up even when histology and count are unchanged.

Case sources: [1]

Case 3

Show answer and explanations

A. Colonoscopy in 3 years (Why this does not fit)
Five to ten small tubular adenomas support 3-year surveillance. Only two lesions have that histology. A total polyp count is not interchangeable with an adenoma count.
Reasoning steps for option A
1. Which adenoma count, size, or histology finding would make 'Colonoscopy in 3 years' appropriate in polyp-03?
  Five to ten small tubular adenomas support 3-year surveillance.
2. Which pathology-classification finding in polyp-03 argues against 'Colonoscopy in 3 years'?
  Only two lesions have that histology.
3. Which adenoma count, size, or histology distinction from polyp-03 should guide a similar decision about 'Colonoscopy in 3 years'?
  A total polyp count is not interchangeable with an adenoma count.
B. Colonoscopy in 3 to 5 years (Why this does not fit)
Three or four small tubular adenomas support this range. Neither adding all polyps nor counting only the three hyperplastic polyps gives the adenoma burden. Assign each specimen to its actual family before choosing a row.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make 'Colonoscopy in 3 to 5 years' appropriate in polyp-03?
  Three or four small tubular adenomas support this range.
2. Which adenoma count, size, or histology finding in polyp-03 argues against 'Colonoscopy in 3 to 5 years'?
  Neither adding all polyps nor counting only the three hyperplastic polyps gives the adenoma burden.
3. Which pathology-classification distinction from polyp-03 should guide a similar decision about 'Colonoscopy in 3 to 5 years'?
  Assign each specimen to its actual family before choosing a row.
C. Repeat screening in 10 years (Why this does not fit)
A high-quality examination with only small hyperplastic polyps can support 10-year screening. This examination also found two conventional adenomas. Do not discard the adenomas when another family is numerically more common.
Reasoning steps for option C
1. Which serrated-subtype, size, or count finding would make 'Repeat screening in 10 years' appropriate in polyp-03?
  A high-quality examination with only small hyperplastic polyps can support 10-year screening.
2. Which adenoma count, size, or histology finding in polyp-03 argues against 'Repeat screening in 10 years'?
  This examination also found two conventional adenomas.
3. Which adenoma count, size, or histology distinction from polyp-03 should guide a similar decision about 'Repeat screening in 10 years'?
  Do not discard the adenomas when another family is numerically more common.
D. Colonoscopy in 7 to 10 years (Best answer)
The two small low-grade tubular adenomas determine the conventional-adenoma count. The three tiny rectal hyperplastic polyps do not convert that count to five adenomas. Count the relevant histologic family before applying its surveillance range.
Reasoning steps for option D
1. How many of the lesions count as conventional adenomas?
  The two small low-grade tubular adenomas determine the conventional-adenoma count.
2. Do the remaining specimens change that denominator?
  The three tiny rectal hyperplastic polyps do not convert that count to five adenomas.
3. What should be counted before consulting the interval table?
  Count the relevant histologic family before applying its surveillance range.

Takeaway: Count the relevant histologic family before applying its surveillance range.

Case sources: [1]

Case 4

Show answer and explanations

A. 5 to 10 years (Why this does not fit)
One or two small nondysplastic SSLs support this range. Four SSLs exceed that count category. A small diameter does not negate multiplicity.
Reasoning steps for option A
1. Which serrated-subtype, size, or count finding would make '5 to 10 years' appropriate in polyp-04?
  One or two small nondysplastic SSLs support this range.
2. Which serrated-subtype, size, or count finding in polyp-04 argues against '5 to 10 years'?
  Four SSLs exceed that count category.
3. Which size-threshold distinction from polyp-04 should guide a similar decision about '5 to 10 years'?
  A small diameter does not negate multiplicity.
B. 3 to 5 years (Best answer)
Three or four SSLs under 10 mm without dysplasia form this surveillance group. The stated count, sizes and complete high-quality excision meet its assumptions. Count SSLs within the serrated recommendations rather than borrowing the tubular-adenoma range.
Reasoning steps for option B
1. Which serrated count category applies?
  Three or four SSLs under 10 mm without dysplasia form this surveillance group.
2. Are the prerequisites for that category met?
  The stated count, sizes and complete high-quality excision meet its assumptions.
3. Which table should be used?
  Count SSLs within the serrated recommendations rather than borrowing the tubular-adenoma range.
C. 7 to 10 years (Why this does not fit)
One or two small tubular adenomas support this range. These lesions are SSLs and there are four of them. Histologic family determines which interval table applies.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-04?
  One or two small tubular adenomas support this range.
2. Which serrated-subtype, size, or count finding in polyp-04 argues against '7 to 10 years'?
  These lesions are SSLs and there are four of them.
3. Which pathology-classification distinction from polyp-04 should guide a similar decision about '7 to 10 years'?
  Histologic family determines which interval table applies.
D. 10 years (Why this does not fit)
Only small confidently classified hyperplastic polyps can support this screening interval in the appropriate population. These are SSLs, not a set of tiny distal hyperplastic polyps. Not every serrated lesion is a low-risk hyperplastic polyp.
Reasoning steps for option D
1. Which serrated-subtype, size, or count finding would make '10 years' appropriate in polyp-04?
  Only small confidently classified hyperplastic polyps can support this screening interval in the appropriate population.
2. Which serrated-subtype, size, or count finding in polyp-04 argues against '10 years'?
  These are SSLs, not a set of tiny distal hyperplastic polyps.
3. Which serrated-subtype, size, or count distinction from polyp-04 should guide a similar decision about '10 years'?
  Not every serrated lesion is a low-risk hyperplastic polyp.

Takeaway: Count SSLs within the serrated recommendations rather than borrowing the tubular-adenoma range.

Case sources: [1]

Case 5

Show answer and explanations

A. Repeat surveillance colonoscopy in 7 to 10 years (Why this does not fit)
A single small low-grade tubular adenoma can support that interval after a high-quality examination. Reliable inspection was not achieved in the ascending colon. Appropriate pathology does not compensate for a failed examination prerequisite.
Reasoning steps for option A
1. Which adenoma count, size, or histology finding would make 'Repeat surveillance colonoscopy in 7 to 10 years' appropriate in polyp-05?
  A single small low-grade tubular adenoma can support that interval after a high-quality examination.
2. Which case-specific finding in polyp-05 argues against 'Repeat surveillance colonoscopy in 7 to 10 years'?
  Reliable inspection was not achieved in the ascending colon.
3. Which pathology-classification distinction from polyp-05 should guide a similar decision about 'Repeat surveillance colonoscopy in 7 to 10 years'?
  Appropriate pathology does not compensate for a failed examination prerequisite.
B. Repeat an adequately prepared colonoscopy within 12 months (Best answer)
Reaching the cecum does not establish that the intervening mucosa was adequately seen. The preparation prevents assigning the usual interval after a single small adenoma. Correct an inadequate screening examination before relying on routine post-polypectomy surveillance.
Reasoning steps for option B
1. Does cecal intubation prove adequate mucosal inspection?
  Reaching the cecum does not establish that the intervening mucosa was adequately seen.
2. Can the standard small-adenoma interval be assigned here?
  The preparation prevents assigning the usual interval after a single small adenoma.
3. What must be corrected before ordinary surveillance is used?
  Correct an inadequate screening examination before relying on routine post-polypectomy surveillance.
C. Inspect only the adenoma scar in 6 months (Why this does not fit)
A focused early site concern can follow large piecemeal resection. The scar is not the unresolved issue; a substantial colonic segment was inadequately assessed. Match the next examination to the actual source of uncertainty.
Reasoning steps for option C
1. Which resection-method or completeness finding would make 'Inspect only the adenoma scar in 6 months' appropriate in polyp-05?
  A focused early site concern can follow large piecemeal resection.
2. Which case-specific finding in polyp-05 argues against 'Inspect only the adenoma scar in 6 months'?
  The scar is not the unresolved issue; a substantial colonic segment was inadequately assessed.
3. Which case-specific distinction from polyp-05 should guide a similar decision about 'Inspect only the adenoma scar in 6 months'?
  Match the next examination to the actual source of uncertainty.
D. Repeat screening in 10 years after a negative stool test (Why this does not fit)
Stool-based testing is a screening option for appropriately assessed average-risk patients. A stool test does not complete the inadequately inspected colon described here. Do not use a negative screening assay to certify missing endoscopic inspection.
Reasoning steps for option D
1. Which screening-pathway finding would make 'Repeat screening in 10 years after a negative stool test' appropriate in polyp-05?
  Stool-based testing is a screening option for appropriately assessed average-risk patients.
2. Which case-specific finding in polyp-05 argues against 'Repeat screening in 10 years after a negative stool test'?
  A stool test does not complete the inadequately inspected colon described here.
3. Which screening-pathway distinction from polyp-05 should guide a similar decision about 'Repeat screening in 10 years after a negative stool test'?
  Do not use a negative screening assay to certify missing endoscopic inspection.

Takeaway: Correct an inadequate screening examination before relying on routine post-polypectomy surveillance.

Case sources: [1] [5]

Case 6

Show answer and explanations

A. Arrange routine completion at the 12-month point (Why this does not fit)
Completion within 12 months is the general recommendation after inadequate screening or surveillance preparation. An unresolved positive stool test calls for a more prompt diagnostic examination. Do not turn an outer completion limit into a reason to wait when diagnostic urgency is greater.
Reasoning steps for option A
1. Which examination-quality finding would make 'Arrange routine completion at the 12-month point' appropriate in polyp-06?
  Completion within 12 months is the general recommendation after inadequate screening or surveillance preparation.
2. Which case-specific finding in polyp-06 argues against 'Arrange routine completion at the 12-month point'?
  An unresolved positive stool test calls for a more prompt diagnostic examination.
3. Which case-specific distinction from polyp-06 should guide a similar decision about 'Arrange routine completion at the 12-month point'?
  Do not turn an outer completion limit into a reason to wait when diagnostic urgency is greater.
B. Use the small-polyp interval of 10 years (Why this does not fit)
Only small confidently classified hyperplastic polyps can support a long interval after an adequate examination. The colon was not adequately inspected and the positive screening result remains unresolved. A tiny incidental distal polyp does not explain away an incomplete diagnostic assessment.
Reasoning steps for option B
1. Which examination-quality finding would make 'Use the small-polyp interval of 10 years' appropriate in polyp-06?
  Only small confidently classified hyperplastic polyps can support a long interval after an adequate examination.
2. Which screening-pathway finding in polyp-06 argues against 'Use the small-polyp interval of 10 years'?
  The colon was not adequately inspected and the positive screening result remains unresolved.
3. Which case-specific distinction from polyp-06 should guide a similar decision about 'Use the small-polyp interval of 10 years'?
  A tiny incidental distal polyp does not explain away an incomplete diagnostic assessment.
C. Repeat the stool test before scheduling colonoscopy (Why this does not fit)
Stool testing can initiate a screening evaluation. A second stool result cannot supply the inspection missing from this diagnostic colonoscopy. After a positive screening test and an inadequate colonoscopy, complete the diagnostic examination rather than restarting screening.
Reasoning steps for option C
1. Which screening-pathway finding would make 'Repeat the stool test before scheduling colonoscopy' appropriate in polyp-06?
  Stool testing can initiate a screening evaluation.
2. Which case-specific finding in polyp-06 argues against 'Repeat the stool test before scheduling colonoscopy'?
  A second stool result cannot supply the inspection missing from this diagnostic colonoscopy.
3. Which screening-pathway distinction from polyp-06 should guide a similar decision about 'Repeat the stool test before scheduling colonoscopy'?
  After a positive screening test and an inadequate colonoscopy, complete the diagnostic examination rather than restarting screening.
D. Arrange prompt completion, usually within 3 months (Best answer)
The inadequate examination has not resolved the positive screening result. The 2025 preparation guidance recommends repeat as soon as possible, usually within 3 months, in this setting. A diagnostic indication can require faster completion than the general within-12-month inadequate-screening recommendation.
Reasoning steps for option D
1. Has the initial positive test been adequately evaluated?
  The inadequate examination has not resolved the positive screening result.
2. How does that indication affect the repeat timing?
  The 2025 preparation guidance recommends repeat as soon as possible, usually within 3 months, in this setting.
3. Which scheduling distinction matters in another inadequate examination?
  A diagnostic indication can require faster completion than the general within-12-month inadequate-screening recommendation.

Takeaway: A diagnostic indication can require faster completion than the general within-12-month inadequate-screening recommendation.

Case sources: [5]

Case 7

Show answer and explanations

A. Sessile serrated lesion; epigenetic mismatch-repair silencing (Best answer)
The distorted basal crypt architecture supports an SSL. MLH1 promoter methylation can silence mismatch repair and permit microsatellite errors to accumulate. Interpret architecture and repair-gene expression together; this pattern does not itself establish an inherited syndrome.
Reasoning steps for option A
1. Which precursor fits the crypt-base architecture?
  The distorted basal crypt architecture supports an SSL.
2. What does MLH1 promoter methylation explain?
  MLH1 promoter methylation can silence mismatch repair and permit microsatellite errors to accumulate.
3. What cannot be inferred about inheritance from this pattern?
  Interpret architecture and repair-gene expression together; this pattern does not itself establish an inherited syndrome.
B. Sessile serrated lesion; proven inherited mismatch-repair loss (Why this does not fit)
SSL architecture is compatible with the tissue description. Promoter methylation in a lesional focus is not proof of a constitutional pathogenic variant. A tumor-associated molecular finding and a germline diagnosis require different evidence.
Reasoning steps for option B
1. Which serrated-subtype, size, or count finding would make 'Sessile serrated lesion; proven inherited mismatch-repair loss' appropriate in polyp-07?
  SSL architecture is compatible with the tissue description.
2. Which case-specific finding in polyp-07 argues against 'Sessile serrated lesion; proven inherited mismatch-repair loss'?
  Promoter methylation in a lesional focus is not proof of a constitutional pathogenic variant.
3. Which case-specific distinction from polyp-07 should guide a similar decision about 'Sessile serrated lesion; proven inherited mismatch-repair loss'?
  A tumor-associated molecular finding and a germline diagnosis require different evidence.
C. Conventional adenoma; APC-mediated chromosomal instability (Why this does not fit)
Conventional adenomas can participate in an APC-associated neoplasia pathway. The supplied basal serrated architecture and MLH1 silencing point to a different precursor and repair defect. Use the actual tissue and molecular findings rather than assigning every polyp the conventional pathway.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make 'Conventional adenoma; APC-mediated chromosomal instability' appropriate in polyp-07?
  Conventional adenomas can participate in an APC-associated neoplasia pathway.
2. Which serrated-subtype, size, or count finding in polyp-07 argues against 'Conventional adenoma; APC-mediated chromosomal instability'?
  The supplied basal serrated architecture and MLH1 silencing point to a different precursor and repair defect.
3. Which case-specific distinction from polyp-07 should guide a similar decision about 'Conventional adenoma; APC-mediated chromosomal instability'?
  Use the actual tissue and molecular findings rather than assigning every polyp the conventional pathway.
D. Traditional serrated adenoma; KRAS-driven signaling (Why this does not fit)
Some traditional serrated adenomas show KRAS-associated signaling changes. The described SSL-type bases and loss of MLH1 expression are not explained by assigning the lesion to that alternative. A serrated surface alone does not make all serrated lesions biologically interchangeable.
Reasoning steps for option D
1. Which adenoma count, size, or histology finding would make 'Traditional serrated adenoma; KRAS-driven signaling' appropriate in polyp-07?
  Some traditional serrated adenomas show KRAS-associated signaling changes.
2. Which serrated-subtype, size, or count finding in polyp-07 argues against 'Traditional serrated adenoma; KRAS-driven signaling'?
  The described SSL-type bases and loss of MLH1 expression are not explained by assigning the lesion to that alternative.
3. Which serrated-subtype, size, or count distinction from polyp-07 should guide a similar decision about 'Traditional serrated adenoma; KRAS-driven signaling'?
  A serrated surface alone does not make all serrated lesions biologically interchangeable.

Takeaway: Interpret architecture and repair-gene expression together; this pattern does not itself establish an inherited syndrome.

Case sources: [4]

Case 8

Show answer and explanations

A. 5 to 10 years (Why this does not fit)
This range applies to one or two SSLs under 10 mm without dysplasia. The lesion is a traditional serrated adenoma, not a small nondysplastic SSL. Serrated subtypes have different follow-up rules.
Reasoning steps for option A
1. Which serrated-subtype, size, or count finding would make '5 to 10 years' appropriate in polyp-08?
  This range applies to one or two SSLs under 10 mm without dysplasia.
2. Which adenoma count, size, or histology finding in polyp-08 argues against '5 to 10 years'?
  The lesion is a traditional serrated adenoma, not a small nondysplastic SSL.
3. Which serrated-subtype, size, or count distinction from polyp-08 should guide a similar decision about '5 to 10 years'?
  Serrated subtypes have different follow-up rules.
B. 7 to 10 years (Why this does not fit)
This range applies to one or two small low-grade tubular adenomas. The pathology identifies a serrated precursor rather than that conventional-adenoma category. A small polyp is not enough information to select the tubular-adenoma range.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-08?
  This range applies to one or two small low-grade tubular adenomas.
2. Which adenoma count, size, or histology finding in polyp-08 argues against '7 to 10 years'?
  The pathology identifies a serrated precursor rather than that conventional-adenoma category.
3. Which adenoma count, size, or histology distinction from polyp-08 should guide a similar decision about '7 to 10 years'?
  A small polyp is not enough information to select the tubular-adenoma range.
C. 3 years (Best answer)
A completely removed traditional serrated adenoma supports 3-year surveillance. Its 8 mm size does not place it in the 1-to-2 small nondysplastic SSL group. Identify the serrated subtype before applying size-based intervals.
Reasoning steps for option C
1. Which recommendation applies to the identified subtype?
  A completely removed traditional serrated adenoma supports 3-year surveillance.
2. Does its small size change that subtype-specific recommendation?
  Its 8 mm size does not place it in the 1-to-2 small nondysplastic SSL group.
3. Which distinction should precede a size-based interval decision?
  Identify the serrated subtype before applying size-based intervals.
D. 10 years (Why this does not fit)
Only low-risk findings such as small hyperplastic polyps can support this screening interval in the appropriate setting. A traditional serrated adenoma is not a routine diminutive hyperplastic polyp. Do not equate a serrated label with absence of precursor risk.
Reasoning steps for option D
1. Which serrated-subtype, size, or count finding would make '10 years' appropriate in polyp-08?
  Only low-risk findings such as small hyperplastic polyps can support this screening interval in the appropriate setting.
2. Which adenoma count, size, or histology finding in polyp-08 argues against '10 years'?
  A traditional serrated adenoma is not a routine diminutive hyperplastic polyp.
3. Which serrated-subtype, size, or count distinction from polyp-08 should guide a similar decision about '10 years'?
  Do not equate a serrated label with absence of precursor risk.

Takeaway: Identify the serrated subtype before applying size-based intervals.

Case sources: [1] [4]

Case 9

Show answer and explanations

A. 3-year surveillance with genetic-risk assessment (Why this does not fit)
Genetic-risk assessment is appropriate for this young patient with substantial burden. A 3-year interval applies to five to ten small adenomas, not the 14 found here. Small size does not cancel the more-than-10 single-examination recommendation.
Reasoning steps for option A
1. Which polyposis-count finding would make '3-year surveillance with genetic-risk assessment' appropriate in polyp-09?
  Genetic-risk assessment is appropriate for this young patient with substantial burden.
2. Which adenoma count, size, or histology finding in polyp-09 argues against '3-year surveillance with genetic-risk assessment'?
  A 3-year interval applies to five to ten small adenomas, not the 14 found here.
3. Which size-threshold distinction from polyp-09 should guide a similar decision about '3-year surveillance with genetic-risk assessment'?
  Small size does not cancel the more-than-10 single-examination recommendation.
B. 1-year surveillance without hereditary assessment (Why this does not fit)
The proposed interval fits the single-examination count. Absence of an affected relative does not exclude a hereditary explanation for numerous adenomas at this age. Use age and cumulative phenotype as well as family history when assessing genetic risk.
Reasoning steps for option B
1. Which case-specific finding would make '1-year surveillance without hereditary assessment' appropriate in polyp-09?
  The proposed interval fits the single-examination count.
2. Which family-history finding in polyp-09 argues against '1-year surveillance without hereditary assessment'?
  Absence of an affected relative does not exclude a hereditary explanation for numerous adenomas at this age.
3. Which family-history distinction from polyp-09 should guide a similar decision about '1-year surveillance without hereditary assessment'?
  Use age and cumulative phenotype as well as family history when assessing genetic risk.
C. 3-year surveillance with a definitive APC diagnosis (Why this does not fit)
An APC-associated syndrome can cause numerous adenomas. The count neither supports the proposed interval nor proves a particular causal gene. A polyp phenotype can prompt genetic evaluation without establishing the molecular diagnosis.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make '3-year surveillance with a definitive APC diagnosis' appropriate in polyp-09?
  An APC-associated syndrome can cause numerous adenomas.
2. Which case-specific finding in polyp-09 argues against '3-year surveillance with a definitive APC diagnosis'?
  The count neither supports the proposed interval nor proves a particular causal gene.
3. Which polyposis-count distinction from polyp-09 should guide a similar decision about '3-year surveillance with a definitive APC diagnosis'?
  A polyp phenotype can prompt genetic evaluation without establishing the molecular diagnosis.
D. 1-year surveillance with genetic-risk assessment (Best answer)
More than 10 adenomas at a single high-quality examination supports 1-year surveillance. The young age and adenoma burden justify assessment for hereditary polyposis despite the reported family history. Separate the surveillance count rule from the evaluation of a possible inherited predisposition.
Reasoning steps for option D
1. Which count determines the surveillance interval?
  More than 10 adenomas at a single high-quality examination supports 1-year surveillance.
2. Why does hereditary assessment remain relevant?
  The young age and adenoma burden justify assessment for hereditary polyposis despite the reported family history.
3. Which two decisions should remain distinct?
  Separate the surveillance count rule from the evaluation of a possible inherited predisposition.

Takeaway: Separate the surveillance count rule from the evaluation of a possible inherited predisposition.

Case sources: [1]

Case 10

Show answer and explanations

A. Assess genetic risk; the 1-year count rule is automatically met (Why this does not fit)
The cumulative total is relevant to genetic-risk assessment. The 1-year recommendation cited in the note uses a single-examination count, not this arithmetic sum. A valid genetic-risk threshold is not automatically the same surveillance threshold.
Reasoning steps for option A
1. Which polyposis-count finding would make 'Assess genetic risk; the 1-year count rule is automatically met' appropriate in polyp-10?
  The cumulative total is relevant to genetic-risk assessment.
2. Which size-threshold finding in polyp-10 argues against 'Assess genetic risk; the 1-year count rule is automatically met'?
  The 1-year recommendation cited in the note uses a single-examination count, not this arithmetic sum.
3. Which size-threshold distinction from polyp-10 should guide a similar decision about 'Assess genetic risk; the 1-year count rule is automatically met'?
  A valid genetic-risk threshold is not automatically the same surveillance threshold.
B. Assess genetic risk; the 1-year count rule is not automatically met (Best answer)
Six plus three plus four equals 13 cumulative adenomas. That lifetime total can support genetic assessment but is not a finding of more than 10 at the latest examination. Use cumulative burden for hereditary assessment and the full serial history for surveillance rather than substituting one count for another.
Reasoning steps for option B
1. What is the actual lifetime total?
  Six plus three plus four equals 13 cumulative adenomas.
2. Does that total satisfy the single-examination rule?
  That lifetime total can support genetic assessment but is not a finding of more than 10 at the latest examination.
3. How should the two types of count be used?
  Use cumulative burden for hereditary assessment and the full serial history for surveillance rather than substituting one count for another.
C. Defer genetic assessment until at least 100 adenomas are found (Why this does not fit)
Hundreds of adenomas can occur in classic polyposis. Hereditary assessment may be appropriate with more than 10 cumulative adenomas, interpreted with age and phenotype. Do not wait for a classic high-burden presentation before considering hereditary disease.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make 'Defer genetic assessment until at least 100 adenomas are found' appropriate in polyp-10?
  Hundreds of adenomas can occur in classic polyposis.
2. Which adenoma count, size, or histology finding in polyp-10 argues against 'Defer genetic assessment until at least 100 adenomas are found'?
  Hereditary assessment may be appropriate with more than 10 cumulative adenomas, interpreted with age and phenotype.
3. Which case-specific distinction from polyp-10 should guide a similar decision about 'Defer genetic assessment until at least 100 adenomas are found'?
  Do not wait for a classic high-burden presentation before considering hereditary disease.
D. Defer genetic assessment unless a relative develops polyposis (Why this does not fit)
An affected relative would strengthen concern for hereditary disease. The patient's cumulative phenotype can itself justify assessment despite an unrevealing family history. A negative reported family history is not an exclusion test for genetic predisposition.
Reasoning steps for option D
1. Which family-history finding would make 'Defer genetic assessment unless a relative develops polyposis' appropriate in polyp-10?
  An affected relative would strengthen concern for hereditary disease.
2. Which family-history finding in polyp-10 argues against 'Defer genetic assessment unless a relative develops polyposis'?
  The patient's cumulative phenotype can itself justify assessment despite an unrevealing family history.
3. Which family-history distinction from polyp-10 should guide a similar decision about 'Defer genetic assessment unless a relative develops polyposis'?
  A negative reported family history is not an exclusion test for genetic predisposition.

Takeaway: Use cumulative burden for hereditary assessment and the full serial history for surveillance rather than substituting one count for another.

Case sources: [1]

Case 11

Show answer and explanations

A. The three-to-four-small-SSL pathway (Why this does not fit)
Three or four small SSLs at one appropriate examination can support a 3-to-5-year interval. This answer ignores cumulative qualifying lesions and the two lesions at least 10 mm. Do not isolate today's count when an inherited-risk or polyposis assessment uses cumulative findings.
Reasoning steps for option A
1. Which serrated-subtype, size, or count finding would make 'The three-to-four-small-SSL pathway' appropriate in polyp-11?
  Three or four small SSLs at one appropriate examination can support a 3-to-5-year interval.
2. Which size-threshold finding in polyp-11 argues against 'The three-to-four-small-SSL pathway'?
  This answer ignores cumulative qualifying lesions and the two lesions at least 10 mm.
3. Which polyposis-count distinction from polyp-11 should guide a similar decision about 'The three-to-four-small-SSL pathway'?
  Do not isolate today's count when an inherited-risk or polyposis assessment uses cumulative findings.
B. The large-hyperplastic-polyp pathway (Why this does not fit)
An isolated HP at least 10 mm can support a 3-to-5-year range. The complete phenotype meets a syndrome criterion, not merely an isolated large-HP category. Check for polyposis before applying individual-lesion surveillance rules.
Reasoning steps for option B
1. Which size-threshold finding would make 'The large-hyperplastic-polyp pathway' appropriate in polyp-11?
  An isolated HP at least 10 mm can support a 3-to-5-year range.
2. Which case-specific finding in polyp-11 argues against 'The large-hyperplastic-polyp pathway'?
  The complete phenotype meets a syndrome criterion, not merely an isolated large-HP category.
3. Which polyposis-count distinction from polyp-11 should guide a similar decision about 'The large-hyperplastic-polyp pathway'?
  Check for polyposis before applying individual-lesion surveillance rules.
C. A serrated-polyposis surveillance pathway (Best answer)
All six lesions count toward the cumulative serrated phenotype regardless of whether pathology calls them HP or SSL. There are at least five proximal-to-rectum lesions at least 5 mm, including two at least 10 mm. Syndrome-level cumulative criteria supersede ordinary average-risk small-polyp surveillance.
Reasoning steps for option C
1. Which histologic subtypes count toward the serrated total?
  All six lesions count toward the cumulative serrated phenotype regardless of whether pathology calls them HP or SSL.
2. Do both size requirements of the first criterion hold?
  There are at least five proximal-to-rectum lesions at least 5 mm, including two at least 10 mm.
3. What follows when a syndrome criterion is met?
  Syndrome-level cumulative criteria supersede ordinary average-risk small-polyp surveillance.
D. The five-to-ten-conventional-adenoma pathway (Why this does not fit)
That conventional-adenoma category supports a 3-year interval. The lesions are serrated and meet a serrated-polyposis definition. Histologic families are not interchangeable counting units.
Reasoning steps for option D
1. Which adenoma count, size, or histology finding would make 'The five-to-ten-conventional-adenoma pathway' appropriate in polyp-11?
  That conventional-adenoma category supports a 3-year interval.
2. Which serrated-subtype, size, or count finding in polyp-11 argues against 'The five-to-ten-conventional-adenoma pathway'?
  The lesions are serrated and meet a serrated-polyposis definition.
3. Which pathology-classification distinction from polyp-11 should guide a similar decision about 'The five-to-ten-conventional-adenoma pathway'?
  Histologic families are not interchangeable counting units.

Takeaway: Syndrome-level cumulative criteria supersede ordinary average-risk small-polyp surveillance.

Case sources: [6]

Case 12

Show answer and explanations

A. No; the cumulative number-and-distribution criterion is met (Best answer)
The second WHO 2019 criterion uses more than 20 serrated lesions overall, with at least five proximal to the rectum. It does not require the 5 mm and 10 mm size thresholds used in the first criterion. Apply each alternative criterion on its own terms and count across examinations.
Reasoning steps for option A
1. Which alternative WHO criterion fits the total and distribution?
  The second WHO 2019 criterion uses more than 20 serrated lesions overall, with at least five proximal to the rectum.
2. Are minimum sizes required by that alternative?
  It does not require the 5 mm and 10 mm size thresholds used in the first criterion.
3. How should alternative definitions be applied?
  Apply each alternative criterion on its own terms and count across examinations.
B. Yes; both polyposis criteria require lesions at least 5 mm (Why this does not fit)
Minimum lesion sizes are part of the first WHO criterion. They are not requirements of the alternative more-than-20 criterion satisfied here. Do not transfer a restriction from one alternative definition to another.
Reasoning steps for option B
1. Which size-threshold finding would make 'Yes; both polyposis criteria require lesions at least 5 mm' appropriate in polyp-12?
  Minimum lesion sizes are part of the first WHO criterion.
2. Which case-specific finding in polyp-12 argues against 'Yes; both polyposis criteria require lesions at least 5 mm'?
  They are not requirements of the alternative more-than-20 criterion satisfied here.
3. Which case-specific distinction from polyp-12 should guide a similar decision about 'Yes; both polyposis criteria require lesions at least 5 mm'?
  Do not transfer a restriction from one alternative definition to another.
C. Yes; no single examination found more than 20 lesions (Why this does not fit)
A single-examination count matters for some ordinary surveillance categories. Serrated-polyposis assessment uses cumulative counts across examinations. A repeated low count can still accumulate into a syndrome-defining phenotype.
Reasoning steps for option C
1. Which case-specific finding would make 'Yes; no single examination found more than 20 lesions' appropriate in polyp-12?
  A single-examination count matters for some ordinary surveillance categories.
2. Which serrated-subtype, size, or count finding in polyp-12 argues against 'Yes; no single examination found more than 20 lesions'?
  Serrated-polyposis assessment uses cumulative counts across examinations.
3. Which case-specific distinction from polyp-12 should guide a similar decision about 'Yes; no single examination found more than 20 lesions'?
  A repeated low count can still accumulate into a syndrome-defining phenotype.
D. No; more than 20 polyps proves an APC-associated syndrome (Why this does not fit)
A substantial polyp burden warrants attention to a polyposis phenotype. These are serrated polyps, and the phenotype does not prove an APC genotype. Use tissue type and distribution to select the syndrome assessment rather than naming a gene from total count alone.
Reasoning steps for option D
1. Which polyposis-count finding would make 'No; more than 20 polyps proves an APC-associated syndrome' appropriate in polyp-12?
  A substantial polyp burden warrants attention to a polyposis phenotype.
2. Which serrated-subtype, size, or count finding in polyp-12 argues against 'No; more than 20 polyps proves an APC-associated syndrome'?
  These are serrated polyps, and the phenotype does not prove an APC genotype.
3. Which case-specific distinction from polyp-12 should guide a similar decision about 'No; more than 20 polyps proves an APC-associated syndrome'?
  Use tissue type and distribution to select the syndrome assessment rather than naming a gene from total count alone.

Takeaway: Apply each alternative criterion on its own terms and count across examinations.

Case sources: [6]

Case 13

Show answer and explanations

A. Routine advanced-adenoma surveillance alone (Why this does not fit)
A completely excised noninvasive advanced adenoma can support 3-year surveillance. This lesion is invasive and has lymphovascular invasion. Do not apply the noninvasive adenoma table to a malignant polyp.
Reasoning steps for option A
1. Which invasion-depth finding would make 'Routine advanced-adenoma surveillance alone' appropriate in polyp-13?
  A completely excised noninvasive advanced adenoma can support 3-year surveillance.
2. Which invasion-depth finding in polyp-13 argues against 'Routine advanced-adenoma surveillance alone'?
  This lesion is invasive and has lymphovascular invasion.
3. Which invasion-depth distinction from polyp-13 should guide a similar decision about 'Routine advanced-adenoma surveillance alone'?
  Do not apply the noninvasive adenoma table to a malignant polyp.
B. Mucosal scar ablation as the complete treatment (Why this does not fit)
Local endoscopic treatment can address residual mucosal neoplasia. The margins are clear, while the adverse finding concerns invasive disease and potential spread beyond the mucosa. A local scar procedure does not address every malignant-polyp risk.
Reasoning steps for option B
1. Which resection-method or completeness finding would make 'Mucosal scar ablation as the complete treatment' appropriate in polyp-13?
  Local endoscopic treatment can address residual mucosal neoplasia.
2. Which invasion-depth finding in polyp-13 argues against 'Mucosal scar ablation as the complete treatment'?
  The margins are clear, while the adverse finding concerns invasive disease and potential spread beyond the mucosa.
3. Which case-specific distinction from polyp-13 should guide a similar decision about 'Mucosal scar ablation as the complete treatment'?
  A local scar procedure does not address every malignant-polyp risk.
C. Colorectal surgical and oncologic assessment (Best answer)
Submucosal invasion establishes a malignant polyp rather than only a mucosal advanced adenoma. Lymphovascular invasion is an adverse feature that is not neutralized by a clear local margin. Local clearance and risk beyond the resection site must be assessed separately before treating polypectomy as definitive cancer care.
Reasoning steps for option C
1. Which tissue boundary has the cancer crossed?
  Submucosal invasion establishes a malignant polyp rather than only a mucosal advanced adenoma.
2. Does the negative margin cancel the adverse vascular finding?
  Lymphovascular invasion is an adverse feature that is not neutralized by a clear local margin.
3. What distinction is necessary before declaring local treatment definitive?
  Local clearance and risk beyond the resection site must be assessed separately before treating polypectomy as definitive cancer care.
D. Definitive polypectomy without additional cancer assessment (Why this does not fit)
Selected malignant polyps with favorable features can be managed after complete endoscopic removal. Definite lymphovascular invasion prevents assuming a favorable low-risk profile here. Assess the complete malignant-polyp risk profile rather than relying on one reassuring margin result.
Reasoning steps for option D
1. Which case-specific finding would make 'Definitive polypectomy without additional cancer assessment' appropriate in polyp-13?
  Selected malignant polyps with favorable features can be managed after complete endoscopic removal.
2. Which invasion-depth finding in polyp-13 argues against 'Definitive polypectomy without additional cancer assessment'?
  Definite lymphovascular invasion prevents assuming a favorable low-risk profile here.
3. Which case-specific distinction from polyp-13 should guide a similar decision about 'Definitive polypectomy without additional cancer assessment'?
  Assess the complete malignant-polyp risk profile rather than relying on one reassuring margin result.

Takeaway: Local clearance and risk beyond the resection site must be assessed separately before treating polypectomy as definitive cancer care.

Case sources: [3]

Case 14

Show answer and explanations

A. A: malignant-lesion assessment; B: advanced endoscopic resection (Why this does not fit)
An invasive-appearing lesion merits malignant-lesion assessment. This pairing assigns that concern to A and overlooks the explicit deep-invasion pattern in B. Do not reverse a referral decision by treating complexity as invasion and invasion as mere complexity.
Reasoning steps for option A
1. Which invasion-depth finding would make 'A: malignant-lesion assessment; B: advanced endoscopic resection' appropriate in polyp-14?
  An invasive-appearing lesion merits malignant-lesion assessment.
2. Which invasion-depth finding in polyp-14 argues against 'A: malignant-lesion assessment; B: advanced endoscopic resection'?
  This pairing assigns that concern to A and overlooks the explicit deep-invasion pattern in B.
3. Which invasion-depth distinction from polyp-14 should guide a similar decision about 'A: malignant-lesion assessment; B: advanced endoscopic resection'?
  Do not reverse a referral decision by treating complexity as invasion and invasion as mere complexity.
B. A: advanced endoscopic resection; B: advanced endoscopic resection (Why this does not fit)
Expert endoscopic treatment is appropriate for many large nonpedunculated benign-appearing lesions. The NICE type 3 finding in B raises a different oncologic concern. Expertise in resection does not eliminate the need to recognize deep-invasion features.
Reasoning steps for option B
1. Which case-specific finding would make 'A: advanced endoscopic resection; B: advanced endoscopic resection' appropriate in polyp-14?
  Expert endoscopic treatment is appropriate for many large nonpedunculated benign-appearing lesions.
2. Which case-specific finding in polyp-14 argues against 'A: advanced endoscopic resection; B: advanced endoscopic resection'?
  The NICE type 3 finding in B raises a different oncologic concern.
3. Which invasion-depth distinction from polyp-14 should guide a similar decision about 'A: advanced endoscopic resection; B: advanced endoscopic resection'?
  Expertise in resection does not eliminate the need to recognize deep-invasion features.
C. A: malignant-lesion assessment; B: malignant-lesion assessment (Why this does not fit)
Patient B's findings justify that pathway. Patient A has no described deep-invasion finding and may avoid unnecessary surgery through expert endoscopic treatment. Large size alone does not require the same cancer pathway as an invasive surface pattern.
Reasoning steps for option C
1. Which case-specific finding would make 'A: malignant-lesion assessment; B: malignant-lesion assessment' appropriate in polyp-14?
  Patient B's findings justify that pathway.
2. Which invasion-depth finding in polyp-14 argues against 'A: malignant-lesion assessment; B: malignant-lesion assessment'?
  Patient A has no described deep-invasion finding and may avoid unnecessary surgery through expert endoscopic treatment.
3. Which invasion-depth distinction from polyp-14 should guide a similar decision about 'A: malignant-lesion assessment; B: malignant-lesion assessment'?
  Large size alone does not require the same cancer pathway as an invasive surface pattern.
D. A: advanced endoscopic resection; B: malignant-lesion assessment (Best answer)
Size and local technical limitations alone do not establish invasive cancer in patient A. Patient B's deep-invasion pattern requires a malignant-lesion pathway rather than routine piecemeal excision. Choose the referral from both technical feasibility and invasion risk, not diameter alone.
Reasoning steps for option D
1. What does size and technical difficulty establish in A?
  Size and local technical limitations alone do not establish invasive cancer in patient A.
2. What additional concern is present in B?
  Patient B's deep-invasion pattern requires a malignant-lesion pathway rather than routine piecemeal excision.
3. Which two dimensions determine the referral?
  Choose the referral from both technical feasibility and invasion risk, not diameter alone.

Takeaway: Choose the referral from both technical feasibility and invasion risk, not diameter alone.

Case sources: [2] [3]

Case 15

Show answer and explanations

A. 1 year, initially assessing the high adenoma burden (Why this does not fit)
More than 10 adenomas at one examination supports a 1-year interval. The qualifying large piecemeal resection requires a first examination before that count-based date. A valid surveillance rule can still be superseded by an earlier resection-specific indication.
Reasoning steps for option A
1. Which adenoma count, size, or histology finding would make '1 year, initially assessing the high adenoma burden' appropriate in polyp-15?
  More than 10 adenomas at one examination supports a 1-year interval.
2. Which resection-method or completeness finding in polyp-15 argues against '1 year, initially assessing the high adenoma burden'?
  The qualifying large piecemeal resection requires a first examination before that count-based date.
3. Which resection-method or completeness distinction from polyp-15 should guide a similar decision about '1 year, initially assessing the high adenoma burden'?
  A valid surveillance rule can still be superseded by an earlier resection-specific indication.
B. 6 months, initially assessing the piecemeal resection site (Best answer)
Exactly 20 mm is included in the large-piecemeal recommendation. The 6-month site-assessment indication precedes the 1-year indication from the adenoma count, while the rest of the colon is also examined. When multiple indications coexist, identify the earliest applicable examination and its purpose.
Reasoning steps for option B
1. Does the SSL meet the inclusive resection threshold?
  Exactly 20 mm is included in the large-piecemeal recommendation.
2. Which applicable interval comes first?
  The 6-month site-assessment indication precedes the 1-year indication from the adenoma count, while the rest of the colon is also examined.
3. How should concurrent surveillance indications be prioritized?
  When multiple indications coexist, identify the earliest applicable examination and its purpose.
C. 3 years, initially assessing the large serrated precursor (Why this does not fit)
A completely excised SSL at least 10 mm ordinarily supports 3-year surveillance. Both the piecemeal resection and the adenoma multiplicity supply earlier indications here. Do not select the routine size category without integrating count and removal method.
Reasoning steps for option C
1. Which serrated-subtype, size, or count finding would make '3 years, initially assessing the large serrated precursor' appropriate in polyp-15?
  A completely excised SSL at least 10 mm ordinarily supports 3-year surveillance.
2. Which resection-method or completeness finding in polyp-15 argues against '3 years, initially assessing the large serrated precursor'?
  Both the piecemeal resection and the adenoma multiplicity supply earlier indications here.
3. Which size-threshold distinction from polyp-15 should guide a similar decision about '3 years, initially assessing the large serrated precursor'?
  Do not select the routine size category without integrating count and removal method.
D. 5 to 10 years, initially assessing the serrated fragments (Why this does not fit)
One or two SSLs under 10 mm without dysplasia can support this range. The original SSL was 20 mm; small retrieved fragments do not redefine its original size, and the adenoma count also excludes this plan. Use original lesion dimensions and the complete polyp profile rather than fragment size alone.
Reasoning steps for option D
1. Which serrated-subtype, size, or count finding would make '5 to 10 years, initially assessing the serrated fragments' appropriate in polyp-15?
  One or two SSLs under 10 mm without dysplasia can support this range.
2. Which adenoma count, size, or histology finding in polyp-15 argues against '5 to 10 years, initially assessing the serrated fragments'?
  The original SSL was 20 mm; small retrieved fragments do not redefine its original size, and the adenoma count also excludes this plan.
3. Which size-threshold distinction from polyp-15 should guide a similar decision about '5 to 10 years, initially assessing the serrated fragments'?
  Use original lesion dimensions and the complete polyp profile rather than fragment size alone.

Takeaway: When multiple indications coexist, identify the earliest applicable examination and its purpose.

Case sources: [1] [2]

Case 16

Show answer and explanations

A. Unrecognized residual tissue at the original resection site (Best answer)
Negative findings in separate fragments do not establish a continuous completely cleared outer boundary. Small residual or recurrent adenoma can persist at the scar after apparently complete piecemeal removal. The early examination tests local eradication rather than predicting inevitable malignant transformation.
Reasoning steps for option A
1. What can separate negative fragments fail to establish?
  Negative findings in separate fragments do not establish a continuous completely cleared outer boundary.
2. Where is the immediate residual-tissue concern located?
  Small residual or recurrent adenoma can persist at the scar after apparently complete piecemeal removal.
3. What does the early examination test?
  The early examination tests local eradication rather than predicting inevitable malignant transformation.
B. Metachronous adenomas elsewhere in the colon (Why this does not fit)
Future adenomas at other sites are an important reason for longer-term surveillance. They do not explain why an unreconstructable specimen boundary specifically prompts an early scar assessment. Distinguish local eradication from future neoplasia elsewhere, even though the colonoscopy can assess both.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make 'Metachronous adenomas elsewhere in the colon' appropriate in polyp-16?
  Future adenomas at other sites are an important reason for longer-term surveillance.
2. Which pathology-classification finding in polyp-16 argues against 'Metachronous adenomas elsewhere in the colon'?
  They do not explain why an unreconstructable specimen boundary specifically prompts an early scar assessment.
3. Which case-specific distinction from polyp-16 should guide a similar decision about 'Metachronous adenomas elsewhere in the colon'?
  Distinguish local eradication from future neoplasia elsewhere, even though the colonoscopy can assess both.
C. Missed synchronous polyps from inadequate preparation (Why this does not fit)
Poor preparation can leave existing lesions undetected and require early completion. The examination was high quality; the stated limitation concerns the resected specimen boundary. Identify whether uncertainty arises from inspection quality or removal quality before choosing its explanation.
Reasoning steps for option C
1. Which examination-quality finding would make 'Missed synchronous polyps from inadequate preparation' appropriate in polyp-16?
  Poor preparation can leave existing lesions undetected and require early completion.
2. Which pathology-classification finding in polyp-16 argues against 'Missed synchronous polyps from inadequate preparation'?
  The examination was high quality; the stated limitation concerns the resected specimen boundary.
3. Which case-specific distinction from polyp-16 should guide a similar decision about 'Missed synchronous polyps from inadequate preparation'?
  Identify whether uncertainty arises from inspection quality or removal quality before choosing its explanation.
D. Regional lymph-node metastases from invasive carcinoma (Why this does not fit)
An invasive malignant polyp can require assessment of regional spread. No invasion is identified here, and scar colonoscopy does not stage regional nodes. Do not substitute cancer staging for a local mucosal-eradication assessment.
Reasoning steps for option D
1. Which invasion-depth finding would make 'Regional lymph-node metastases from invasive carcinoma' appropriate in polyp-16?
  An invasive malignant polyp can require assessment of regional spread.
2. Which invasion-depth finding in polyp-16 argues against 'Regional lymph-node metastases from invasive carcinoma'?
  No invasion is identified here, and scar colonoscopy does not stage regional nodes.
3. Which case-specific distinction from polyp-16 should guide a similar decision about 'Regional lymph-node metastases from invasive carcinoma'?
  Do not substitute cancer staging for a local mucosal-eradication assessment.

Takeaway: The early examination tests local eradication rather than predicting inevitable malignant transformation.

Case sources: [1] [2]

Case 17

Show answer and explanations

A. 3 years after this surveillance examination (Why this does not fit)
Three years is a later interval in the large-piecemeal sequence. It follows the second surveillance, not the first early scar examination. Do not skip the intervening 1-year surveillance step.
Reasoning steps for option A
1. Which resection-method or completeness finding would make '3 years after this surveillance examination' appropriate in polyp-17?
  Three years is a later interval in the large-piecemeal sequence.
2. Which case-specific finding in polyp-17 argues against '3 years after this surveillance examination'?
  It follows the second surveillance, not the first early scar examination.
3. Which case-specific distinction from polyp-17 should guide a similar decision about '3 years after this surveillance examination'?
  Do not skip the intervening 1-year surveillance step.
B. 6 months after this surveillance examination (Why this does not fit)
An early recheck can be appropriate if residual or recurrent tissue requires treatment. This scar is clear and no other reason for another early eradication check is supplied. A repeated 6-month interval is not the automatic schedule after every clear examination.
Reasoning steps for option B
1. Which resection-method or completeness finding would make '6 months after this surveillance examination' appropriate in polyp-17?
  An early recheck can be appropriate if residual or recurrent tissue requires treatment.
2. Which case-specific finding in polyp-17 argues against '6 months after this surveillance examination'?
  This scar is clear and no other reason for another early eradication check is supplied.
3. Which case-specific distinction from polyp-17 should guide a similar decision about '6 months after this surveillance examination'?
  A repeated 6-month interval is not the automatic schedule after every clear examination.
C. 10 years after this surveillance examination (Why this does not fit)
A normal average-risk screening examination can support a 10-year interval. This is surveillance after large piecemeal resection, not a new average-risk baseline. A clear scar does not erase the indication for the planned follow-up sequence.
Reasoning steps for option C
1. Which screening-pathway finding would make '10 years after this surveillance examination' appropriate in polyp-17?
  A normal average-risk screening examination can support a 10-year interval.
2. Which resection-method or completeness finding in polyp-17 argues against '10 years after this surveillance examination'?
  This is surveillance after large piecemeal resection, not a new average-risk baseline.
3. Which case-specific distinction from polyp-17 should guide a similar decision about '10 years after this surveillance examination'?
  A clear scar does not erase the indication for the planned follow-up sequence.
D. 1 year after this surveillance examination (Best answer)
The large-piecemeal pathway begins with an examination at about 6 months. After a clear first surveillance, the next recommended examination is 1 year later, followed by 3 years after the second surveillance if appropriate. Measure each subsequent interval from the preceding surveillance examination in this sequence.
Reasoning steps for option D
1. Which surveillance pathway was established by the original resection?
  The large-piecemeal pathway begins with an examination at about 6 months.
2. What is the next interval after the first clear examination?
  After a clear first surveillance, the next recommended examination is 1 year later, followed by 3 years after the second surveillance if appropriate.
3. From which examination should the interval be measured?
  Measure each subsequent interval from the preceding surveillance examination in this sequence.

Takeaway: Measure each subsequent interval from the preceding surveillance examination in this sequence.

Case sources: [2]

Case 18

Show answer and explanations

A. Treat residual tissue endoscopically and reassess eradication (Best answer)
The scar contains demonstrable residual adenoma rather than a completely cleared site. Noninvasive histology supports appropriate local treatment but does not justify leaving the tissue in place. Restore confidence in eradication before advancing to a routine longer surveillance interval.
Reasoning steps for option A
1. What does the scar biopsy establish?
  The scar contains demonstrable residual adenoma rather than a completely cleared site.
2. Does noninvasive histology make untreated tissue acceptable?
  Noninvasive histology supports appropriate local treatment but does not justify leaving the tissue in place.
3. What must precede routine longer-interval surveillance?
  Restore confidence in eradication before advancing to a routine longer surveillance interval.
B. Observe the nodule and resume 3-year surveillance (Why this does not fit)
Three-year surveillance can follow complete excision of an advanced adenoma. The finding is untreated residual adenoma, not merely a historical advanced-adenoma risk. A surveillance date is not a substitute for completing treatment.
Reasoning steps for option B
1. Which resection-method or completeness finding would make 'Observe the nodule and resume 3-year surveillance' appropriate in polyp-18?
  Three-year surveillance can follow complete excision of an advanced adenoma.
2. Which resection-method or completeness finding in polyp-18 argues against 'Observe the nodule and resume 3-year surveillance'?
  The finding is untreated residual adenoma, not merely a historical advanced-adenoma risk.
3. Which case-specific distinction from polyp-18 should guide a similar decision about 'Observe the nodule and resume 3-year surveillance'?
  A surveillance date is not a substitute for completing treatment.
C. Classify the nodule as a new low-risk baseline polyp (Why this does not fit)
An isolated small low-grade tubular adenoma can fit a lower-risk group after complete removal. This lesion is at a prior large-piecemeal resection scar and was only biopsied. Interpret pathology together with site and treatment status rather than size alone.
Reasoning steps for option C
1. Which resection-method or completeness finding would make 'Classify the nodule as a new low-risk baseline polyp' appropriate in polyp-18?
  An isolated small low-grade tubular adenoma can fit a lower-risk group after complete removal.
2. Which resection-method or completeness finding in polyp-18 argues against 'Classify the nodule as a new low-risk baseline polyp'?
  This lesion is at a prior large-piecemeal resection scar and was only biopsied.
3. Which size-threshold distinction from polyp-18 should guide a similar decision about 'Classify the nodule as a new low-risk baseline polyp'?
  Interpret pathology together with site and treatment status rather than size alone.
D. Select colectomy solely because the adenoma recurred (Why this does not fit)
Surgery can be appropriate when endoscopic treatment is unsuitable or cancer risk demands it. A small noninvasive residual nodule does not by itself establish either condition. Recurrent mucosal adenoma warrants an appropriate eradication plan, not an automatic assumption of invasive cancer.
Reasoning steps for option D
1. Which case-specific finding would make 'Select colectomy solely because the adenoma recurred' appropriate in polyp-18?
  Surgery can be appropriate when endoscopic treatment is unsuitable or cancer risk demands it.
2. Which invasion-depth finding in polyp-18 argues against 'Select colectomy solely because the adenoma recurred'?
  A small noninvasive residual nodule does not by itself establish either condition.
3. Which invasion-depth distinction from polyp-18 should guide a similar decision about 'Select colectomy solely because the adenoma recurred'?
  Recurrent mucosal adenoma warrants an appropriate eradication plan, not an automatic assumption of invasive cancer.

Takeaway: Restore confidence in eradication before advancing to a routine longer surveillance interval.

Case sources: [2]

Case 19

Show answer and explanations

A. Observe until a routine 6-month scar inspection (Why this does not fit)
An approximately 6-month examination is recommended after qualifying large piecemeal resection. This is a known incompletely treated 18 mm lesion, not just uncertainty after apparent clearance of a lesion at least 20 mm. Do not use a surveillance threshold as permission to leave known residual tissue untreated.
Reasoning steps for option A
1. Which resection-method or completeness finding would make 'Observe until a routine 6-month scar inspection' appropriate in polyp-19?
  An approximately 6-month examination is recommended after qualifying large piecemeal resection.
2. Which size-threshold finding in polyp-19 argues against 'Observe until a routine 6-month scar inspection'?
  This is a known incompletely treated 18 mm lesion, not just uncertainty after apparent clearance of a lesion at least 20 mm.
3. Which resection-method or completeness distinction from polyp-19 should guide a similar decision about 'Observe until a routine 6-month scar inspection'?
  Do not use a surveillance threshold as permission to leave known residual tissue untreated.
B. Assign the 3-year advanced-adenoma interval (Why this does not fit)
An 18 mm adenoma meets an advanced-size criterion. The ordinary interval presumes confident complete removal, which the report explicitly denies. Check resection completeness before applying a lesion-risk interval.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make 'Assign the 3-year advanced-adenoma interval' appropriate in polyp-19?
  An 18 mm adenoma meets an advanced-size criterion.
2. Which resection-method or completeness finding in polyp-19 argues against 'Assign the 3-year advanced-adenoma interval'?
  The ordinary interval presumes confident complete removal, which the report explicitly denies.
3. Which resection-method or completeness distinction from polyp-19 should guide a similar decision about 'Assign the 3-year advanced-adenoma interval'?
  Check resection completeness before applying a lesion-risk interval.
C. Refer promptly for expert completion of endoscopic treatment (Best answer)
The remaining visible rim establishes incomplete removal. Being below 20 mm does not convert known residual adenoma into a completed resection suitable for routine surveillance. Complete treatment of known residual tissue rather than waiting for a threshold-based surveillance date.
Reasoning steps for option C
1. What does the visible residual rim establish?
  The remaining visible rim establishes incomplete removal.
2. Does the sub-20 mm size resolve that problem?
  Being below 20 mm does not convert known residual adenoma into a completed resection suitable for routine surveillance.
3. What must be completed before surveillance rules can be used?
  Complete treatment of known residual tissue rather than waiting for a threshold-based surveillance date.
D. Choose surgical resection because the lesion exceeds 10 mm (Why this does not fit)
Size at least 10 mm changes the surveillance risk category after appropriate treatment. It does not itself prove invasion or preclude expert endoscopic completion. Distinguish a risk-classification threshold from an indication for surgery.
Reasoning steps for option D
1. Which size-threshold finding would make 'Choose surgical resection because the lesion exceeds 10 mm' appropriate in polyp-19?
  Size at least 10 mm changes the surveillance risk category after appropriate treatment.
2. Which invasion-depth finding in polyp-19 argues against 'Choose surgical resection because the lesion exceeds 10 mm'?
  It does not itself prove invasion or preclude expert endoscopic completion.
3. Which size-threshold distinction from polyp-19 should guide a similar decision about 'Choose surgical resection because the lesion exceeds 10 mm'?
  Distinguish a risk-classification threshold from an indication for surgery.

Takeaway: Complete treatment of known residual tissue rather than waiting for a threshold-based surveillance date.

Case sources: [1] [2]

Case 20

Show answer and explanations

A. 3 years (Why this does not fit)
Three years is the initial surveillance interval after complete removal of an advanced adenoma. The subsequent normal examination supports a longer next interval in the serial-surveillance table. Reassess the plan using both baseline and first-surveillance results.
Reasoning steps for option A
1. Which resection-method or completeness finding would make '3 years' appropriate in polyp-20?
  Three years is the initial surveillance interval after complete removal of an advanced adenoma.
2. Which case-specific finding in polyp-20 argues against '3 years'?
  The subsequent normal examination supports a longer next interval in the serial-surveillance table.
3. Which baseline-and-surveillance distinction from polyp-20 should guide a similar decision about '3 years'?
  Reassess the plan using both baseline and first-surveillance results.
B. 5 years (Best answer)
The baseline lesion belongs to the advanced-adenoma group despite tubular architecture. A normal first surveillance permits extension to 5 years, rather than treating the history as a new normal baseline. A reassuring surveillance result modifies prior risk without erasing the baseline findings.
Reasoning steps for option B
1. Which baseline category did the 12 mm lesion establish?
  The baseline lesion belongs to the advanced-adenoma group despite tubular architecture.
2. How does a normal first surveillance change the next interval?
  A normal first surveillance permits extension to 5 years, rather than treating the history as a new normal baseline.
3. What principle explains why the next interval is not 10 years?
  A reassuring surveillance result modifies prior risk without erasing the baseline findings.
C. 7 to 10 years (Why this does not fit)
That range is used for one or two small low-grade tubular adenomas in the relevant setting. The baseline adenoma was 12 mm, so its tubular architecture does not make it a small-adenoma baseline. Use size as well as architecture when preserving a patient's prior risk category.
Reasoning steps for option C
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-20?
  That range is used for one or two small low-grade tubular adenomas in the relevant setting.
2. Which adenoma count, size, or histology finding in polyp-20 argues against '7 to 10 years'?
  The baseline adenoma was 12 mm, so its tubular architecture does not make it a small-adenoma baseline.
3. Which size-threshold distinction from polyp-20 should guide a similar decision about '7 to 10 years'?
  Use size as well as architecture when preserving a patient's prior risk category.
D. 10 years (Why this does not fit)
A normal first surveillance after one or two small tubular adenomas can support 10 years. This patient's baseline was advanced by size. The same normal surveillance report can lead to different next intervals depending on the earlier examination.
Reasoning steps for option D
1. Which adenoma count, size, or histology finding would make '10 years' appropriate in polyp-20?
  A normal first surveillance after one or two small tubular adenomas can support 10 years.
2. Which baseline-and-surveillance finding in polyp-20 argues against '10 years'?
  This patient's baseline was advanced by size.
3. Which case-specific distinction from polyp-20 should guide a similar decision about '10 years'?
  The same normal surveillance report can lead to different next intervals depending on the earlier examination.

Takeaway: A reassuring surveillance result modifies prior risk without erasing the baseline findings.

Case sources: [1]

Case 21

Show answer and explanations

A. A: 7 to 10 years; B: 5 years (Best answer)
Patient A has a small-adenoma baseline followed by another one-to-two-small-adenoma finding. Patient B retains an advanced-adenoma baseline, for which one or two small adenomas at first surveillance support 5 years. Identical current pathology does not guarantee identical follow-up when baseline histories differ.
Reasoning steps for option A
1. Which serial small-adenoma category applies to A?
  Patient A has a small-adenoma baseline followed by another one-to-two-small-adenoma finding.
2. What earlier finding still affects B?
  Patient B retains an advanced-adenoma baseline, for which one or two small adenomas at first surveillance support 5 years.
3. Why can matching current reports yield different next intervals?
  Identical current pathology does not guarantee identical follow-up when baseline histories differ.
B. A: 7 to 10 years; B: 7 to 10 years (Why this does not fit)
Patient A fits the proposed small-adenoma serial category. The pairing discards patient B's advanced-size baseline. Do not replace a serial-surveillance assessment with the current-examination table alone.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make 'A: 7 to 10 years; B: 7 to 10 years' appropriate in polyp-21?
  Patient A fits the proposed small-adenoma serial category.
2. Which baseline-and-surveillance finding in polyp-21 argues against 'A: 7 to 10 years; B: 7 to 10 years'?
  The pairing discards patient B's advanced-size baseline.
3. Which case-specific distinction from polyp-21 should guide a similar decision about 'A: 7 to 10 years; B: 7 to 10 years'?
  Do not replace a serial-surveillance assessment with the current-examination table alone.
C. A: 5 years; B: 5 years (Why this does not fit)
A 5-year interval fits the stated serial findings in patient B. Patient A has no advanced baseline finding to support assigning B's category to both. Preserve differences in earlier risk rather than making paired cases artificially equivalent.
Reasoning steps for option C
1. Which case-specific finding would make 'A: 5 years; B: 5 years' appropriate in polyp-21?
  A 5-year interval fits the stated serial findings in patient B.
2. Which baseline-and-surveillance finding in polyp-21 argues against 'A: 5 years; B: 5 years'?
  Patient A has no advanced baseline finding to support assigning B's category to both.
3. Which case-specific distinction from polyp-21 should guide a similar decision about 'A: 5 years; B: 5 years'?
  Preserve differences in earlier risk rather than making paired cases artificially equivalent.
D. A: 7 to 10 years; B: 3 years (Why this does not fit)
Three years was appropriate as patient B's initial interval after the advanced baseline. The first surveillance now shows only two small low-grade tubular adenomas, supporting 5 years for B. An initial interval need not persist unchanged after a lower-risk surveillance result.
Reasoning steps for option D
1. Which baseline-and-surveillance finding would make 'A: 7 to 10 years; B: 3 years' appropriate in polyp-21?
  Three years was appropriate as patient B's initial interval after the advanced baseline.
2. Which adenoma count, size, or histology finding in polyp-21 argues against 'A: 7 to 10 years; B: 3 years'?
  The first surveillance now shows only two small low-grade tubular adenomas, supporting 5 years for B.
3. Which case-specific distinction from polyp-21 should guide a similar decision about 'A: 7 to 10 years; B: 3 years'?
  An initial interval need not persist unchanged after a lower-risk surveillance result.

Takeaway: Identical current pathology does not guarantee identical follow-up when baseline histories differ.

Case sources: [1]

Case 22

Show answer and explanations

A. 7 to 10 years (Why this does not fit)
That range fits one or two small tubular adenomas in the relevant category. The current two polyps are hyperplastic, not tubular adenomas. A report's total number of polyps does not specify its serial-surveillance category.
Reasoning steps for option A
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-22?
  That range fits one or two small tubular adenomas in the relevant category.
2. Which adenoma count, size, or histology finding in polyp-22 argues against '7 to 10 years'?
  The current two polyps are hyperplastic, not tubular adenomas.
3. Which case-specific distinction from polyp-22 should guide a similar decision about '7 to 10 years'?
  A report's total number of polyps does not specify its serial-surveillance category.
B. 5 years (Why this does not fit)
Five years can follow an advanced baseline adenoma and a normal first surveillance. The original 6 mm low-grade tubular adenoma was not advanced. Preserve the actual baseline rather than assigning a higher-risk history from the word adenoma alone.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make '5 years' appropriate in polyp-22?
  Five years can follow an advanced baseline adenoma and a normal first surveillance.
2. Which adenoma count, size, or histology finding in polyp-22 argues against '5 years'?
  The original 6 mm low-grade tubular adenoma was not advanced.
3. Which adenoma count, size, or histology distinction from polyp-22 should guide a similar decision about '5 years'?
  Preserve the actual baseline rather than assigning a higher-risk history from the word adenoma alone.
C. 10 years (Best answer)
Only small hyperplastic polyps do not create an adenoma-positive first-surveillance category. A one-to-two-small-adenoma baseline followed by a normal first surveillance supports a 10-year next interval. Translate the new pathology into the correct surveillance category before combining it with the baseline.
Reasoning steps for option C
1. How should the current small-HP finding be classified for this table?
  Only small hyperplastic polyps do not create an adenoma-positive first-surveillance category.
2. What does that result mean when combined with the baseline?
  A one-to-two-small-adenoma baseline followed by a normal first surveillance supports a 10-year next interval.
3. Which interpretation must occur before using the serial interval?
  Translate the new pathology into the correct surveillance category before combining it with the baseline.
D. 3 years (Why this does not fit)
A new advanced adenoma or sufficiently high adenoma burden can support 3 years. Neither is present at either examination described. Do not shorten surveillance merely because two tiny nonadenomatous polyps were removed.
Reasoning steps for option D
1. Which adenoma count, size, or histology finding would make '3 years' appropriate in polyp-22?
  A new advanced adenoma or sufficiently high adenoma burden can support 3 years.
2. Which case-specific finding in polyp-22 argues against '3 years'?
  Neither is present at either examination described.
3. Which adenoma count, size, or histology distinction from polyp-22 should guide a similar decision about '3 years'?
  Do not shorten surveillance merely because two tiny nonadenomatous polyps were removed.

Takeaway: Translate the new pathology into the correct surveillance category before combining it with the baseline.

Case sources: [1]

Case 23

Show answer and explanations

A. A: 3 years; B: 5 years (Why this does not fit)
Both numbers lie within the large-HP range. The stated guideline preference is reversed: greater diagnostic uncertainty favors the shorter endpoint. A reassuring pathology service does not justify assigning a shorter endpoint than an uncertain one by this rule.
Reasoning steps for option A
1. Which case-specific finding would make 'A: 3 years; B: 5 years' appropriate in polyp-23?
  Both numbers lie within the large-HP range.
2. Which case-specific finding in polyp-23 argues against 'A: 3 years; B: 5 years'?
  The stated guideline preference is reversed: greater diagnostic uncertainty favors the shorter endpoint.
3. Which pathology-classification distinction from polyp-23 should guide a similar decision about 'A: 3 years; B: 5 years'?
  A reassuring pathology service does not justify assigning a shorter endpoint than an uncertain one by this rule.
B. A: 5 years; B: 3 years (Best answer)
The large-HP recommendation permits a 3-to-5-year interval. Reliable distinction and complete high-quality excision favor 5 years in A, whereas concern about HP-versus-SSL distinction favors 3 in B. Use the specified sources of uncertainty to choose within a guideline range rather than inventing a new histologic diagnosis.
Reasoning steps for option B
1. Which range applies before considering pathology confidence?
  The large-HP recommendation permits a 3-to-5-year interval.
2. How does the stated difference affect the preferred endpoints?
  Reliable distinction and complete high-quality excision favor 5 years in A, whereas concern about HP-versus-SSL distinction favors 3 in B.
3. What should uncertainty change without proving a different diagnosis?
  Use the specified sources of uncertainty to choose within a guideline range rather than inventing a new histologic diagnosis.
C. A: 10 years; B: 3 years (Why this does not fit)
A 10-year interval may fit only small confidently classified HPs in the appropriate context. Patient A's polyp is 12 mm, so high diagnostic confidence does not restore the small-HP category. Size and diagnostic confidence answer separate parts of the follow-up decision.
Reasoning steps for option C
1. Which case-specific finding would make 'A: 10 years; B: 3 years' appropriate in polyp-23?
  A 10-year interval may fit only small confidently classified HPs in the appropriate context.
2. Which size-threshold finding in polyp-23 argues against 'A: 10 years; B: 3 years'?
  Patient A's polyp is 12 mm, so high diagnostic confidence does not restore the small-HP category.
3. Which size-threshold distinction from polyp-23 should guide a similar decision about 'A: 10 years; B: 3 years'?
  Size and diagnostic confidence answer separate parts of the follow-up decision.
D. A: 5 years; B: 6 months (Why this does not fit)
Six-month surveillance initially applies after a qualifying large piecemeal resection. Patient B's lesion is 12 mm, intact and confidently excised; the uncertainty is histologic distinction. Do not equate uncertain subtype classification with the large-piecemeal scar pathway.
Reasoning steps for option D
1. Which resection-method or completeness finding would make 'A: 5 years; B: 6 months' appropriate in polyp-23?
  Six-month surveillance initially applies after a qualifying large piecemeal resection.
2. Which size-threshold finding in polyp-23 argues against 'A: 5 years; B: 6 months'?
  Patient B's lesion is 12 mm, intact and confidently excised; the uncertainty is histologic distinction.
3. Which resection-method or completeness distinction from polyp-23 should guide a similar decision about 'A: 5 years; B: 6 months'?
  Do not equate uncertain subtype classification with the large-piecemeal scar pathway.

Takeaway: Use the specified sources of uncertainty to choose within a guideline range rather than inventing a new histologic diagnosis.

Case sources: [1]

Case 24

Show answer and explanations

A. 3 years (Why this does not fit)
Advanced adenoma or a higher adenoma count can support 3-year surveillance. Neither polyp is advanced, and this family-history rule specifies 5 years rather than 3. Use the actual history-based recommendation rather than shortening to an arbitrary adenoma category.
Reasoning steps for option A
1. Which adenoma count, size, or histology finding would make '3 years' appropriate in polyp-24?
  Advanced adenoma or a higher adenoma count can support 3-year surveillance.
2. Which pathology-classification finding in polyp-24 argues against '3 years'?
  Neither polyp is advanced, and this family-history rule specifies 5 years rather than 3.
3. Which adenoma count, size, or histology distinction from polyp-24 should guide a similar decision about '3 years'?
  Use the actual history-based recommendation rather than shortening to an arbitrary adenoma category.
B. 7 to 10 years (Why this does not fit)
This range fits the two small tubular adenomas considered alone. It omits the father's colorectal cancer before age 60. The average-risk polyp table is not sufficient when a separate family-history pathway applies.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-24?
  This range fits the two small tubular adenomas considered alone.
2. Which family-history finding in polyp-24 argues against '7 to 10 years'?
  It omits the father's colorectal cancer before age 60.
3. Which pathology-classification distinction from polyp-24 should guide a similar decision about '7 to 10 years'?
  The average-risk polyp table is not sufficient when a separate family-history pathway applies.
C. 10 years (Why this does not fit)
A normal average-risk screening examination can support 10 years. This patient has both adenomas and a family history supporting a shorter interval. Complete local polyp excision does not remove familial risk.
Reasoning steps for option C
1. Which screening-pathway finding would make '10 years' appropriate in polyp-24?
  A normal average-risk screening examination can support 10 years.
2. Which family-history finding in polyp-24 argues against '10 years'?
  This patient has both adenomas and a family history supporting a shorter interval.
3. Which case-specific distinction from polyp-24 should guide a similar decision about '10 years'?
  Complete local polyp excision does not remove familial risk.
D. 5 years (Best answer)
The polyp findings alone would support a 7-to-10-year interval after complete high-quality excision. The stated first-degree-relative history supports 5-year colonoscopy under ACG guidance, which is shorter. Do not let a low-risk polyp profile override an independently shorter family-history recommendation.
Reasoning steps for option D
1. What interval would the polyps alone support?
  The polyp findings alone would support a 7-to-10-year interval after complete high-quality excision.
2. Which independent history supports a shorter interval?
  The stated first-degree-relative history supports 5-year colonoscopy under ACG guidance, which is shorter.
3. How should the two recommendations be reconciled?
  Do not let a low-risk polyp profile override an independently shorter family-history recommendation.

Takeaway: Do not let a low-risk polyp profile override an independently shorter family-history recommendation.

Case sources: [1] [10]

Case 25

Show answer and explanations

A. Replace 10 years with a 5-to-10-year range (Why this does not fit)
One or two small nondysplastic SSLs support this range. All four lesions were reclassified, so the count exceeds that group. Apply the revised diagnosis to every affected specimen before counting.
Reasoning steps for option A
1. Which serrated-subtype, size, or count finding would make 'Replace 10 years with a 5-to-10-year range' appropriate in polyp-25?
  One or two small nondysplastic SSLs support this range.
2. Which case-specific finding in polyp-25 argues against 'Replace 10 years with a 5-to-10-year range'?
  All four lesions were reclassified, so the count exceeds that group.
3. Which pathology-classification distinction from polyp-25 should guide a similar decision about 'Replace 10 years with a 5-to-10-year range'?
  Apply the revised diagnosis to every affected specimen before counting.
B. Replace 10 years with a 3-to-5-year range (Best answer)
The revised pathology identifies four SSLs rather than only small hyperplastic polyps. Four small nondysplastic SSLs fit the 3-to-5-year surveillance category. A corrected histologic family can change follow-up even when size, count and removal quality are unchanged.
Reasoning steps for option B
1. Which lesion family is established by the review?
  The revised pathology identifies four SSLs rather than only small hyperplastic polyps.
2. What range follows from the revised family and count?
  Four small nondysplastic SSLs fit the 3-to-5-year surveillance category.
3. Which stable variables did not prevent the recommendation from changing?
  A corrected histologic family can change follow-up even when size, count and removal quality are unchanged.
C. Retain the 10-year screening recommendation (Why this does not fit)
Only small confidently classified HPs can support that recommendation in this context. The review establishes a different serrated precursor category. Noninvasive does not mean that SSLs and HPs have interchangeable surveillance intervals.
Reasoning steps for option C
1. Which size-threshold finding would make 'Retain the 10-year screening recommendation' appropriate in polyp-25?
  Only small confidently classified HPs can support that recommendation in this context.
2. Which serrated-subtype, size, or count finding in polyp-25 argues against 'Retain the 10-year screening recommendation'?
  The review establishes a different serrated precursor category.
3. Which invasion-depth distinction from polyp-25 should guide a similar decision about 'Retain the 10-year screening recommendation'?
  Noninvasive does not mean that SSLs and HPs have interchangeable surveillance intervals.
D. Replace 10 years with a 6-month scar examination (Why this does not fit)
Large piecemeal resection can require an early scar assessment. None of these lesions was at least 20 mm, and the reassessment concerns histology rather than residual tissue. A pathology reclassification does not itself create a large-piecemeal resection scenario.
Reasoning steps for option D
1. Which resection-method or completeness finding would make 'Replace 10 years with a 6-month scar examination' appropriate in polyp-25?
  Large piecemeal resection can require an early scar assessment.
2. Which resection-method or completeness finding in polyp-25 argues against 'Replace 10 years with a 6-month scar examination'?
  None of these lesions was at least 20 mm, and the reassessment concerns histology rather than residual tissue.
3. Which resection-method or completeness distinction from polyp-25 should guide a similar decision about 'Replace 10 years with a 6-month scar examination'?
  A pathology reclassification does not itself create a large-piecemeal resection scenario.

Takeaway: A corrected histologic family can change follow-up even when size, count and removal quality are unchanged.

Case sources: [1] [4]

Case 26

Show answer and explanations

A. 10 years (Best answer)
Up to 20 small rectosigmoid HPs can support 10-year follow-up after a high-quality examination. The stated count, size, location and population fit this low-risk finding. Small distal hyperplastic polyps do not automatically shorten the normal screening interval.
Reasoning steps for option A
1. Which count-and-location rule applies?
  Up to 20 small rectosigmoid HPs can support 10-year follow-up after a high-quality examination.
2. Does the described examination meet its assumptions?
  The stated count, size, location and population fit this low-risk finding.
3. What is the transferable small-distal-HP rule?
  Small distal hyperplastic polyps do not automatically shorten the normal screening interval.
B. 7 to 10 years (Why this does not fit)
One or two small low-grade tubular adenomas fit this range. The lesions are hyperplastic rather than conventional adenomas. Use pathology, not merely the presence of two polyps, to select a surveillance category.
Reasoning steps for option B
1. Which adenoma count, size, or histology finding would make '7 to 10 years' appropriate in polyp-26?
  One or two small low-grade tubular adenomas fit this range.
2. Which adenoma count, size, or histology finding in polyp-26 argues against '7 to 10 years'?
  The lesions are hyperplastic rather than conventional adenomas.
3. Which pathology-classification distinction from polyp-26 should guide a similar decision about '7 to 10 years'?
  Use pathology, not merely the presence of two polyps, to select a surveillance category.
C. 5 to 10 years (Why this does not fit)
One or two small nondysplastic SSLs fit this range. The lesions are confidently classified rectal HPs, not SSLs. Different serrated subtypes require different follow-up categories.
Reasoning steps for option C
1. Which serrated-subtype, size, or count finding would make '5 to 10 years' appropriate in polyp-26?
  One or two small nondysplastic SSLs fit this range.
2. Which serrated-subtype, size, or count finding in polyp-26 argues against '5 to 10 years'?
  The lesions are confidently classified rectal HPs, not SSLs.
3. Which serrated-subtype, size, or count distinction from polyp-26 should guide a similar decision about '5 to 10 years'?
  Different serrated subtypes require different follow-up categories.
D. 3 to 5 years (Why this does not fit)
A large HP or three to four small SSLs can fit this range. The two 4 mm rectal HPs meet neither of those descriptions. Size and subtype prevent unnecessary shortening of a low-risk interval.
Reasoning steps for option D
1. Which serrated-subtype, size, or count finding would make '3 to 5 years' appropriate in polyp-26?
  A large HP or three to four small SSLs can fit this range.
2. Which size-threshold finding in polyp-26 argues against '3 to 5 years'?
  The two 4 mm rectal HPs meet neither of those descriptions.
3. Which size-threshold distinction from polyp-26 should guide a similar decision about '3 to 5 years'?
  Size and subtype prevent unnecessary shortening of a low-risk interval.

Takeaway: Small distal hyperplastic polyps do not automatically shorten the normal screening interval.

Case sources: [1]

Case 27

Show answer and explanations

A. Four adenomas; no large-piecemeal surveillance category (Why this does not fit)
The absence of qualifying piecemeal endoscopic resection is correctly recognized. The four processing pieces came from one lesion rather than four separately located adenomas. Histology piece count is not the clinical adenoma denominator.
Reasoning steps for option A
1. Which resection-method or completeness finding would make 'Four adenomas; no large-piecemeal surveillance category' appropriate in polyp-27?
  The absence of qualifying piecemeal endoscopic resection is correctly recognized.
2. Which adenoma count, size, or histology finding in polyp-27 argues against 'Four adenomas; no large-piecemeal surveillance category'?
  The four processing pieces came from one lesion rather than four separately located adenomas.
3. Which adenoma count, size, or histology distinction from polyp-27 should guide a similar decision about 'Four adenomas; no large-piecemeal surveillance category'?
  Histology piece count is not the clinical adenoma denominator.
B. One adenoma; large-piecemeal surveillance category (Why this does not fit)
The original lesion count is correctly preserved. The fragmentation occurred after intact removal, and the lesion was only 8 mm. The surveillance category depends on the original lesion and endoscopic technique, not subsequent processing.
Reasoning steps for option B
1. Which case-specific finding would make 'One adenoma; large-piecemeal surveillance category' appropriate in polyp-27?
  The original lesion count is correctly preserved.
2. Which size-threshold finding in polyp-27 argues against 'One adenoma; large-piecemeal surveillance category'?
  The fragmentation occurred after intact removal, and the lesion was only 8 mm.
3. Which case-specific distinction from polyp-27 should guide a similar decision about 'One adenoma; large-piecemeal surveillance category'?
  The surveillance category depends on the original lesion and endoscopic technique, not subsequent processing.
C. Four adenomas; large-piecemeal surveillance category (Why this does not fit)
Multiple lesions and large piecemeal excision can each affect surveillance in the appropriate setting. Neither is established by four laboratory pieces from one intact 8 mm excision. Reconstruct the procedure before interpreting a specimen inventory as clinical burden or technique.
Reasoning steps for option C
1. Which resection-method or completeness finding would make 'Four adenomas; large-piecemeal surveillance category' appropriate in polyp-27?
  Multiple lesions and large piecemeal excision can each affect surveillance in the appropriate setting.
2. Which size-threshold finding in polyp-27 argues against 'Four adenomas; large-piecemeal surveillance category'?
  Neither is established by four laboratory pieces from one intact 8 mm excision.
3. Which pathology-classification distinction from polyp-27 should guide a similar decision about 'Four adenomas; large-piecemeal surveillance category'?
  Reconstruct the procedure before interpreting a specimen inventory as clinical burden or technique.
D. One adenoma; no large-piecemeal surveillance category (Best answer)
Laboratory processing does not turn one anatomically distinct adenoma into four lesions. An intact 8 mm endoscopic excision is not piecemeal removal of a lesion at least 20 mm. Use the procedure report for original count, size and technique rather than inferring them from laboratory fragments.
Reasoning steps for option D
1. How many anatomically distinct adenomas were removed?
  Laboratory processing does not turn one anatomically distinct adenoma into four lesions.
2. Did the endoscopic procedure meet the large-piecemeal definition?
  An intact 8 mm endoscopic excision is not piecemeal removal of a lesion at least 20 mm.
3. Which record establishes the original clinical variables?
  Use the procedure report for original count, size and technique rather than inferring them from laboratory fragments.

Takeaway: Use the procedure report for original count, size and technique rather than inferring them from laboratory fragments.

Case sources: [1] [2]

Case 28

Show answer and explanations

A. Maintain the surveillance date while replacing iron (Why this does not fit)
Iron replacement can treat iron deficiency. It does not explain the bleeding and weight loss or substitute for evaluation in this patient. Treating a laboratory consequence is not the same as investigating its cause.
Reasoning steps for option A
1. Which case-specific finding would make 'Maintain the surveillance date while replacing iron' appropriate in polyp-28?
  Iron replacement can treat iron deficiency.
2. Which case-specific finding in polyp-28 argues against 'Maintain the surveillance date while replacing iron'?
  It does not explain the bleeding and weight loss or substitute for evaluation in this patient.
3. Which case-specific distinction from polyp-28 should guide a similar decision about 'Maintain the surveillance date while replacing iron'?
  Treating a laboratory consequence is not the same as investigating its cause.
B. Use hemorrhoid treatment as the sole evaluation (Why this does not fit)
Hemorrhoids can cause visible rectal bleeding. A small nonbleeding hemorrhoid does not adequately account for the full set of alarm findings. Do not let an incidental benign finding end the assessment of unexplained anemia and weight loss.
Reasoning steps for option B
1. Which case-specific finding would make 'Use hemorrhoid treatment as the sole evaluation' appropriate in polyp-28?
  Hemorrhoids can cause visible rectal bleeding.
2. Which case-specific finding in polyp-28 argues against 'Use hemorrhoid treatment as the sole evaluation'?
  A small nonbleeding hemorrhoid does not adequately account for the full set of alarm findings.
3. Which case-specific distinction from polyp-28 should guide a similar decision about 'Use hemorrhoid treatment as the sole evaluation'?
  Do not let an incidental benign finding end the assessment of unexplained anemia and weight loss.
C. Arrange prompt diagnostic gastrointestinal evaluation (Best answer)
The new anemia, depleted iron stores and symptoms require assessment for a gastrointestinal cause. The prior surveillance schedule does not establish the source of today's bleeding or exclude a new serious diagnosis. Surveillance intervals govern planned follow-up; new alarm findings create a separate diagnostic problem.
Reasoning steps for option C
1. What current findings require a new assessment?
  The new anemia, depleted iron stores and symptoms require assessment for a gastrointestinal cause.
2. Do the earlier colonoscopy and hemorrhoid establish their cause?
  The prior surveillance schedule does not establish the source of today's bleeding or exclude a new serious diagnosis.
3. How do diagnostic indications differ from surveillance dates?
  Surveillance intervals govern planned follow-up; new alarm findings create a separate diagnostic problem.
D. Use a negative repeat FIT to defer investigation (Why this does not fit)
FIT is useful in appropriate screening pathways. A negative screening test cannot resolve this symptomatic iron-deficiency presentation. Select diagnostic evaluation from the clinical problem rather than restarting average-risk screening.
Reasoning steps for option D
1. Which screening-pathway finding would make 'Use a negative repeat FIT to defer investigation' appropriate in polyp-28?
  FIT is useful in appropriate screening pathways.
2. Which screening-pathway finding in polyp-28 argues against 'Use a negative repeat FIT to defer investigation'?
  A negative screening test cannot resolve this symptomatic iron-deficiency presentation.
3. Which screening-pathway distinction from polyp-28 should guide a similar decision about 'Use a negative repeat FIT to defer investigation'?
  Select diagnostic evaluation from the clinical problem rather than restarting average-risk screening.

Takeaway: Surveillance intervals govern planned follow-up; new alarm findings create a separate diagnostic problem.

Case sources: [1] [11]

Sources

Recommendations for follow-up after colonoscopy and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer (2020)
US surveillance tables 4, 5 and 7; eligibility, inclusive size thresholds, single-examination versus lifetime adenoma counts, and serial surveillance.
Endoscopic Removal of Colorectal Lesions: Recommendations by the US Multi-Society Task Force on Colorectal Cancer (2020)
Complete resection, experienced endoscopist referral, large nonpedunculated lesions, and surveillance after piecemeal resection.
Endoscopic Recognition and Management Strategies for Malignant Colorectal Polyps: Recommendations of the US Multi-Society Task Force on Colorectal Cancer (2020)
Submucosal invasion, deep-invasion appearance, and adverse pathology requiring malignant-polyp assessment rather than ordinary adenoma surveillance.
Serrated Lesions of the Colorectum: Review and Recommendations From an Expert Panel (2012)
Histologic architecture, proximal detection features and serrated-pathway biology only; not its superseded surveillance intervals or polyposis definition.
Optimizing bowel preparation quality for colonoscopy: consensus recommendations by the US Multi-Society Task Force on Colorectal Cancer (2025)
Adequacy judged after cleaning, repeat within 12 months after inadequate screening/surveillance examination, and prompt repeat after an abnormal noncolonoscopic screening test.
Guidelines for the management of hereditary colorectal cancer from the BSG/ACPGBI/UKCGG (2020)
WHO 2019 serrated polyposis criteria, inclusion of all serrated subtypes, cumulative counts, and specialist surveillance outside average-risk tables.
Post-polypectomy colonoscopy surveillance: ESGE Guideline Update 2020 (2020)
Framework comparison only: villous architecture alone does not have the same surveillance consequence in every jurisdiction.
Villous adenoma1.jpg, original histology photograph by Nephron (2009)
Actual villous architecture; selected CC BY-SA 3.0 license, unchanged original photograph.
Sessile serrated adenoma 2 low mag.jpg, original histology photograph by Nephron (2010)
Actual serrated crypt architecture; selected CC BY-SA 3.0 license, unchanged original photograph.
Colon Cancer: ACG screening recommendations
Official ACG recommendation for 5-year colonoscopy when a first-degree relative had colorectal cancer before age 60; publication date of this web page not established.
AGA Clinical Practice Guidelines on the Gastrointestinal Evaluation of Iron Deficiency Anemia (2020)
Diagnostic evaluation of iron-deficiency anemia rather than deferral to a future polyp-surveillance date.

Return to lesson title

Study maps

Colon polyps: tissue, complete removal and follow-up

Does advanced mean invasive?

Was the colon adequately examined and cleared?

Read the tissue before naming the pathway

Use location and count without confusing them

Change the resection, change the first follow-up

A specimen-and-scar experiment

Choose an interval from the complete profile

Apply the tissue, quality and follow-up distinctions

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Case 2

Case 3

Case 4

Case 5

Case 6

Case 7

Case 8

Case 9

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Case 11

Case 12

Case 13

Case 14

Case 15

Case 16

Case 17

Case 18

Case 19

Case 20

Case 21

Case 22

Case 23

Case 24

Case 25

Case 26

Case 27

Case 28

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