The document discusses colorectal polyps, which are discrete tissue masses that protrude into the bowel lumen, and various methods for their detection, including fecal tests, colonoscopy, and imaging techniques. It highlights the characteristics and classification of polyps, emphasizing the risk factors for malignancy and outlining management strategies such as endoscopic resection methods. Additionally, it details the histological features of different polyp types and their implications for colorectal cancer development.

1. Approach to Colorectal Polyp
Dr Awadhesh Narayan
MD. DrNB (Gastro)

3. • A polyp is a discrete mass of tissue that protrudes into the lumen of the
bowel.
• Polyp’ is a term derived from the Greek word polypous, which means
‘morbid lump.’
• Generally, this term describes any mass protruding into the lumen of a
hollow vessel, anywhere in the gastro-intestinal, genito-urinary or
respiratory tracts

4. Methods for Detection
• Colorectal polyps usually are clinically silent.
• They most often are detected either incidentally during investigation
for non-specific symptoms.
• As part of the evaluation for iron deficiency anemia
• or in asymptomatic people being screened for colorectal neoplasia

5. Fecal Occult Blood Testing
• In general, polyps smaller than 1 cm do not bleed.
• polyp detected after a positive test result may be coincidental and that the FOBT
result is not directly attributable to bleeding from the polyp
• Upon colonoscopic evaluation, less than half of these people will have a colorectal
neoplasm, and among the lesions found, adenomas outnumber carcinomas by 3:1.
• false positives can occur if the patient recently had ingested vegetable peroxidases (in
turnips, radishes, melons, broccoli,carrots, cauliflower, cucumbers, grapefruit,
mushrooms) or red meat (containing myoglobin), and false negatives can occur in the
presence of high doses of antioxidants such as vitamin C.
Morikawa T, Kato J, Yamaji Y. Sensitivity of immunochemical fecal occult blood test to small colorectal adenomas. Am J Gastroenterol
2007;102(10):2259–64.

6. Fecal Immunochemical Testing
• To avoid some of the drawbacks of FOBTs, fecal immunochemical
testing (FIT) uses antibody-based detection of human hemoglobin in
the stool.
• the overall sensitivity for detecting any adenoma ranged from 11.4%
to 58.0%, and 25.4% to 71.5% for advanced adenomas.
• detects more cancers than adenomas
Hundt S, Haug U, Brenner H. Comparative evaluation of immunochemical fecal occult blood tests for colorectal
adenoma detection.Ann Intern Med 2009;150(3):162–9.

7. Barium Enema
• The detection of adenomas by barium enema (BE) depends on their
size.
• In the National Polyp Study, the detection ratesof adenomas smaller
than 6 mm, 6 to 10 mm, and larger than 10 mm were 32%, 53%, and
48%, respectively.
Winawer SJ, Stewart ET, Zauber AG, et al. A comparison of colonoscopy and double-contrast barium enema for surveillance afterpolypectomy.
N Engl J Med 2000;342:1766–72.

8. Colonoscopy
• Considered the gold standard for detecting polyps
• Colonoscopy also can miss neoplasms, especially those located at
flexures or behind folds.
• In general, missed adenomas tend to be small.
• Studies had demonstrated adenoma miss rates of 0% to 6% for
adenomas larger than 1 cm, 12% to 13% for adenomas 6 to 9 mm, and
15% to 27% for adenomas smaller than 6 mm.
• NBI did not show an improvement in ADR over high-definition white-
light endoscopy
Rex DK. Maximizing detection of adenomas and cancers during colonoscopy. Am J Gastroenterol 2006;101:2866–77.

9. CT Colonography
• Also known as virtual colonoscopy, CTC involves scanning the colon
with a helical or spiral CT scanner to produce both 2- and 3-
dimensional images of the colon and rectum.
• In the first large study to involve a pure asymptomatic screening
population, CTC had a sensitivity of 86% for polyps 5 to 9 mm and
92% for polyps larger than 10 mm
Pickhardt PJ, Choi JR, Hwang I, et al. Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults. N
Engl J Med 2003;349:2191–200.

10. Stool DNA Testing
• DNA-based CRC screening approaches are based on the premise that
tumor cells are shed into the lumen and abnormal DNA from these
neoplastic lesions will be detectable in the stool.
• fecal DNA testing detected only 42% of advanced adenomatous
polyps.

11. Macroscopic classification
Paris classification-
2 macroscopic types:
• (1) type 0- the superficial lesions
• (2) types 1–5, the advanced cancers

13. According to size polyps are classified into 3 groups:
1. Diminutive (1 to 5 mm)
2. Small (6 to 9 mm)
3. Large (≥10mm)

14. Laterally spreading tumors (LSTs)
• Non-polypoid lesions 10 mm or larger in diameter are referred to as
LSTs
• They have a low vertical axis and extend laterally along the colonic
luminal wall.

15. LSTs are morphologically subclassified
into granular type (LST-G) (A, B), which
have a nodular surface, and non-granular
type (LST-NG), which have a smooth
surface (C, D).
This macroscopic distinction is important
to facilitate the endoscopic removal plan as
it provides information about the risk of
cancer or submucosal fibrosis in order to
anticipate the technical ease or difficulty of
the removal.

16. • LST-G have the lowest risk (0.5%; 95% ), whereas LST-NG have the
highest risk of submucosal invasion (31.6%)
Bogie RMM, Veldman MHJ, Snijders LARS, et al. Endoscopic subtypes of colorectal laterally spreading tumors (LSTs) and the
risk of submucosal invasion: a meta-analysis. Endoscopy 2018;50:263-82.

18. Optical diagnosis
• Endoscopic prediction of the histologic class of a polyp may influence
the resection approach to ensure complete removal.
• optical diagnosis of colorectal lesions is feasible in routine clinical
practice and comparable to the current reference standard,
histopathology.

19. The Narrow Band Imaging International Colorectal Endoscopic (NICE)
classification provides a validated criterion for the classification-
• Type 1 (serrated class lesions–hyperplastic and sessile serrated
lesions)
• Type 2 (adenomas)
• Type 3 (those with deep submucosal invasion).

21. • This classification have achieved 93% concordance of optical
diagnosis and pathology, and a >90% negative predictive value for
rectosigmoid lesions.
ASGE Technology Committee; Abu Dayyeh BK, Thosani N, et al. ASGE Technology Committee systematic review and meta-analysis
Gastrointest Endosc 2015;81:502; e1–e16

22. Workgroup Serrated Polyps and
Polyposis-WASP) criteria added 4
sessile serrated lesion features (ie,
clouded surface, indistinctive
borders, irregular shape, and
dark spots inside crypts) to the
NICE classification

23. • valley sign is highly specific (>90%)
for conventional adenoma in
diminutive (<5 mm) lesions,
suggesting it to be a valid predictor of
adenomatous histology in diminutive
colorectal lesions

24. Its application has been shown to be useful in assessing the most
clinically relevant approaches:
• leave hyperplastic diminutive lesions of the rectum and sigmoid colon
• remove all adenomas anywhere in the colon and any serrated lesions
proximal to sigmoid colon and >5 mm.
• biopsy and refer to surgery lesions with deep submucosal invasion.

25. CONVENTIONALADENOMAS
Histologic Features
• Characterized by abnormal cellular proliferation and renewal, resulting
in hypercellularity of colonic crypts, with cells that appear
hyperchromatic and depleted of mucin with elongated nuclei arranged
in a picket-fence pattern.
• In a study involving 13,992 participants who underwent screening
colonoscopy, 5891 nontumorous polyps were removed; of these, 3469
(59.0%) were adenomatous.
Lieberman D, Moravec M, Holub J, Michaels L, Eisen G. Polyp size and advanced histology in patients undergoing colonoscopy screening:
Gastroenterology 2008; 135: 1100-5.

26. Tubuler Villous Tubullovillous
at least 80% of the
glands are of the
branching tubule
type
20-80% of the glands
are villous
at least 80% of the
glands are of villiform
type

27. • Of all adenomatous polyps, TAs account for 80-86%, tubulovillous for
8-16%, and villous adenomas for 3-16%.
• By definition, all conventional adenomas are dysplastic.
• TAs usually are small and exhibit mild dysplasia, whereas villous
architecture is more often encountered in large adenomas and tends to
be associated with an increased frequency of HGD
Konishi F, Morson BCJ. Pathology of colorectal adenomas: a colonoscopic survey. J Clin Pathol 1982;35:830–41

28. Adenomas are considered advanced-
• if they are 10 mm or more in diameter
• adenomas that are <1 cm in diameter are considered to be advanced if
they contain at least 25% villous features, high-grade dysplasia, or
carcinoma.
Colorectal AdenomasN Engl J Med 2016

29. • If a focus of neoplastic cells grows beyond the basement membrane
into the lamina propria, the lesion is termed intramucosal carcinoma.
• Both HGD and intramucosal carcinoma are noninvasive lesions
without metastatic potential.
• Only when a focus of neoplastic cells has spread through the
muscularis mucosae is the lesion considered invasive carcinoma.
• An adenoma that contains a focus of invasive carcinoma commonly is
referred to as a malignant polyp

31. Malignant Potential of Adenomatous Polyp
• The 3 features that correlate with malignant potential for an
adenomatous polyp are size, histologic type, and degree of dysplasia.
• malignant potential is correlated directly with larger adenoma size,
more villous histology and higher degrees of dysplasia.
• These 3 criteria usually are interdependent.

32. Molecular Pathogenesis
Conventional adenomas and a subset of sessile serrated adenomas
develop through to 3 major pathways:
1. chromosomal instability (CIN)
2. microsatellite instability(MSI).
3. aberrant hypermethylation of CpG island methylator phenotype
(CIMP)
• 85% of sporadic colon cancers arise from conventional adenomas
through the classic adenoma-carcinoma sequence,

34. SERRASTED ADENOMAS
Hyperplastic polyp
Sessile serrated
adenoma
Traditional serrated
adenoma
Histologically these are distinguished
from conventional adenomas
primarily
by a saw-tooth or stellate appearance
of their colonic crypts

35. Hyperplastic Polyp
• HPs, which account for approximately 80% of all serrated lesions.
• characterized by elongated crypts with serrated architecture confined
to the upper half of the crypts.
• proliferation in the basal half of the crypt is regular and non-serrated,
without crowding or cytological atypia.
• HPs are thought to have no malignant potential

36. • HPs are small, round, pale polyps that
are predominantly located in the distal
rectosigmoid colon.
• have absent or thin, lacy overlying
capillaries, and a papillary or stellate
pit pattern.

37. Sessile Serrated Adenoma
• second most common type of serrated lesion (15% to 20%).
• along with TSAs, are considered precursor lesion to CRC arising via
the serrated neoplasia pathway.
• The pathologic hallmarks of SSAs are hyperserration and dilatation
extending to the lower third or the base of the crypt.
• SSAs are also found more commonly in the proximal colon and are
frequently multiple.

38. • SSA are typically larger than HPs,but are also pale and have either a
flat or sessile morphology.
• Distinguishing features of SSA include a cloud-like surface, an
overlying mucus cap, a rim of debris or stool around the lesion, and
obscuration of the underlying mucosal vasculature

40. Traditional serrated adenoma
• TSAs are rare, representing 1% of serrated lesions .
• Grossly, TSAs resemble conventional adenomas in that they are often
polypoid, pedunculated, and are more common in the left colon.
• The presence of ectopic crypt formation appears to be highly specific
to TSAs and is thought to account for the exuberant protuberant
growth associated with TSAs but not SSAs or HPs.

43. GASTROINTESTINAL ENDOSCOPY Volume 91, No. 3 : 2020

44. Diminutive (<5 mm) and small (6–9 mm) lesions
• Cold snare polypectomy to remove diminutive (<5 mm) and small
(6–9 mm) lesions.
• Recommend against the use of cold forceps polypectomy to remove
diminutive lesions due to high rates of incomplete resection.
• For diminutive lesions <2 mm, if cold snare polypectomy is
technically difficult, jumbo or large-capacity forceps polypectomymay
be considered

45. • Recommend against the use of hot biopsy forceps for polypectomy of
diminutive (<5 mm) and small (6–9 mm) lesion.
• Cold resection methods induce less injury to the submucosal arteries
than polypectomy methods using electrocautery and thus, decrease the
risk of delayed bleeding and perforation

46. Non-pedunculated (10–19 mm) lesions
• Suggest cold or hot snare polypectomy (with or without submucosal
injection) to remove 10–19 mm nonpedunculated lesions.
• EMR should be considered for non-polypoid and serrated lesions in
the 10- to 19-mm size.

47. Non-pedunculated (>20 mm) lesions
• Recommend EMR as the preferred treatment method of large (>20
mm) non-pedunculated colorectal lesions.
• We recommend snare resection of all grossly visible tissue of a lesion
in a single colonoscopy session and in the safest minimum number of
pieces.
• Prior failed attempts at resection are associated with higher risk for
incomplete resection or recurrence.

48. • We suggest the use of a contrast agent, such as indigo carmine or
methylene blue, in the submucosal injection solution to facilitate
recognition of the submucosa from the mucosa and muscularis propria
layers
• We recommend against the use of tattoo, as the submucosal injection
solution.
• The carbon particle suspension may result in submucosal fibrosis and
can thus reduce the technical success of future endoscopic resection of
residual or recurrent lesion

49. • We suggest the use of a viscous injection solution (eg, hydroxyethyl
starch, Eleview, ORISE Gel) for lesions>20mm to remove the lesion.

50. • We recommend against the use of ablative techniques (eg APC, snare
tip soft coagulation) on endoscopically visible residual tissue of a
lesion, as they have been associated with an increased risk of
recurrence.
• We suggest the use of adjuvant thermal ablation of the post- EMR
margin, where no endoscopically visible adenoma remains despite
meticulous inspection.

51. ENDOSCOPIC MUCOSAL RESECTION FOR FLAT AND
SERRATED LESIONS
• EMR is the preferred treatment method of large (>20 mm)
nonpedunculated colorectal lesions.
• Inject-and-Cut EMR Technique- most commonly used technique for
removal of large non-pedunculated lesions.

52. Underwater Endoscopic Mucosal Resection
• It obviates the step of submucosal injection before snare resection.
• When the lumen is distended with water the mucosa and submucosa
floats as folds into the non-distended colon, while the muscularis
propria remains circular.
• The segment of lumen with the lesion is completely immersed under
water, the borders of the polyp are marked using APC or snare tip
coagulation, and the hot snare resection is completed

53. Cold Snare Endoscopic Mucosal Resection
• Cold snare with injection is a recently described method to remove large lesions
without electrocautery tominimize the risk of delayed bleeding and perforation
• prospective study- removed 163 serrated lesions >10 mm (median size, 15 mm;
range, 10–40 mm) using an injection of succinylated gelatin and diluted methylene
blue before piecemeal snare resection without diathermy. Short-term surveillance
colonoscopy in 82% of the lesions (n= 134) at 6 months showed a single
recurrence (0.6%).
Tutticci NJ, Hewett DG. Cold EMR of large sessile serrated polyps at colonoscopy. Gastrointest Endosc 2018;87:837–842

55. Endoscopic Submucosal Dissection
• The indications for colorectal ESD are-
• Large-sized (>20 mm in diameter) lesions that are indicated for
endoscopic rather than surgical resection, and in which en bloc
resection using inject-and-cut EMR is difficult.
• These include, lesion suspected to have submucosal invasion (ie, large
depressed lesion or pseudodepressed LST-NG lesion), mucosal lesions
with fibrosis, local residual early carcinoma after endoscopic
resection, and non-polypoid colorectal dysplasia in patients with
inflammatory bowel disease.

56. Pedunculated lesions
• We recommend hot snare polypectomy to remove pedunculated
lesions >10 mm.
• We recommend prophylactic mechanical ligation of the stalk with a
detachable loop or clips on pedunculated lesions with head >20 mm
or with stalk thickness >5 mm to reduce immediate and delayed post-
polypectomy bleeding

59. • studies have shown that individuals with adenoma, despite adenoma
removal, may have increased risk for CRC compared to the general
population
• Surveillance colonoscopy after baseline removal of adenoma with
high-risk features (eg, size ≥10 mm) reduce risk for incident CRC.
• Impact of surveillance colonoscopy after removal of adenoma with
low-risk features (such as 1–2 adenomas <10 mm) on risk for incident
CRC is uncertain

63. For patients with piecemeal resection of adenoma or SSP >20 mm,
repeat colonoscopy in 6 months.

68. • For patients with HP ≥10 mm, repeat colonoscopy in 3–5 years.
• A 3-year follow-up interval is favored if yhere is concern about
pathologist consistency in distinguishing SSPs from HPs or complete
polyp excision.
• 5-year interval is favored if there is low concerns for consistency in
distinguishing between SSP and HP by the pathologist, and confident
complete polyp excision.