This document summarizes colonic neoplastic polyps. It defines polyps and classifies them based on their appearance, size, and whether they have stalks. Adenomas are the most common type of polyp and can be tubular, tubulovillous, or villous based on histology. Dysplasia is also classified from mild to severe. Risk of malignancy increases with polyp size over 1cm, villous histology, higher dysplasia grade, or presence of advanced pathology. Dietary and lifestyle factors can influence polyp risk. Initial treatment is full colonoscopy and polyp removal. Follow-up depends on features of the polyp.

1. COLONIC NEOPLASTIC
POLYPS

2. Definition
A GI polyp is a discrete mass of tissue that protrudes into the
lumen of the bowel.
characterized by its gross
appearance and overall size,
whether or not it has a stalk,
whether it is 1 of multiple similar masses occurring elsewhere in
the GI tract.

3. Classifications

5. Pathology
Histological features
Pedunculated-attached by a stalk
Sessile –attached by broad base with little or no
stalk
By definition, all colorectal adenomas are
dysplastic.

6. World Health Organization,
adenomas are classified
Tubular- if at least 80% of the glands are of the
branching tubule type
Villous -if at least 80% of the glands are villiform.
Of all adenomatous polyps,
tubular adenomas account for 80% to 86%,tubulovillous
for 8% to 16%, and villous adenomas for 3% to16%.

7. Tubular Villous

8. Dysplasia
Mild Dysplasia
Mod Dysplasia
Severe
Dysplasia
Low grade
Dysplasia
High grade
Dysplasia

9. Mild Dysplasia
Mod Dysplasia
Severe Dysplasia

12. Histologic Types of Adenomas
and Their Features

13. Malignant Potential of Polyp
Larger adenoma size >1cm
Villous Adenoma on histology
Higher degrees of dysplasia
Adenoma with advanced pathology(AAP)

14. Flat Polyps
Macroscopically, a flat adenoma is either
completely flat or slightly raised, and can
contain a central depression.
Diameter of this polyp is more than twice its
thickness.
Typically less than 1 cm in diameter, these
lesions can be easily missed at endoscopy.

16. Relation of Adenoma, Histology, and Degree of
Dysplasia to the Incidence of Invasive
Carcinoma by Adenoma Size

17. Pathogenesis
 Adenomatous polyps are thought to arise from
a failure in a step, or steps, of the normal
process of cell proliferation and cell death
(apoptosis).

18. Pathogenesis
Adenoma-carcinoma hypothesis
Epidemiologic Evidence
Clinicopathologic Evidence
Molecular Genetic Evidence

19. Pathway Of Colon
Carcinogenesis

20. Evolution of adenoma &
colon ca

21. Pravalence

22. Anatomic Distribution of Colorectal
Adenomas Based on Autopsy and
Colonoscopy Studies

23. Risk Factors for Susceptibility to
Adenomas
Inherited Susceptibility
Dietary and lifestyle risk factors
Conditions Associated With
Adenomatous Polyps

24. Inherited Susceptibility
Hereditary Polyposis Syndrome
Lynch Syndrome
Probands with first degree relatives
with colon cancer or adenoma
Adenomas in pts with family history
of colon cancer have faster growth
rates
10-30% are familial

25. Dietary and Lifestyle Risk
Factors
excess dietary fat
excess alcohol intake
Obesity(central)
cigarette smoking
dietary fiber,
plant foods
Carbohydrate
Chemoprotective-
NSAIDS,Calcium,
HRT,Selenium
Increased risk Protective

26. Dietary and Lifestyle Risk
Factors

27. Dietary and Lifestyle Risk
Factors

28. Conditions Associated with
Adenomatous Polyps
Ureterosigmoidostomy -29%,20-26yrs later
Acromegaly – Increased IGF,5-25% CRC,14-35%
adenoma
Streptococcus bovis and JC virus
Cholecystectomy-increased bile in colon,
increases proliferation

29. Clinical Features
Usually no symptoms
Occult or Overt bleeding
Constipation,diarrhea and flatulance.
• Intermittant intususception
Cramping abdominal Pain
• Villous,3-4cm,sigmoid or rectal
Secretary Diarrhea
Obstruction

30. Detection
Fecal occult blood testing –
<40% pts adenoma have Positive testing
Asymptomatic >40yrs-1-3% positive
50% will have adenoma colonoscopy
3:1Adenoma Vs CRC
PPV-Adenoma(30-35%),CRC(8-12%)

31. Sigmoidoscopy
Rigid sigmoidoscopy would detect polyps
(of all histologic types) in about 7% of
asymptomatic persons older than 40 years,
flexible sigmoidoscope would find polyps in
10% to 15%,principally because a greater
length of bowel could be examined.
Screening sigmoidoscopy now show
reductions in CRC mortality from 21% to
38%.

32. Colonoscopy
Preferred colon cancer screening
test
Gold standard
• 10% failure caecal intubation
• higher cost, can miss CRC
• Miss rate-0-6%(1cm),
• 12-13%(6to9mm),15-27%(<6mm)
Limitations -
• Adequacy of preparation,caecal intubation rate,withdrawl time and
adenoma detection rate
Miss Rate

33. Current Guidelines-
Caecal intubation rate >90% all,95% for
screening
Adenoma detection rate –At least 15%
Withdrawl time->=6 minutes

34. CT Colonography (virtual
colonoscopy)
2 and 3dimensional CT
Bowel preparation,colon
distended with CO2
Images taken in supine and
prone position
Sensitivity-
86%(5to9mm),92%(>10mm)
Low sensitivity for <5mm
polpyps
Radiation exposure(0.14%)
Incidental findings 70%,11%
Surveilliance interval
Concerns

35. CT colonography CT

36. Newer methods
 Altered human DNA in stool analysis
 3-4 times more sensitive for adenoma
detection

37. Treatment
Untreated adenoma-5-10yrs for CRC
cumulative risk of cancer at the polyp site is 2.5% at 5 years,
8% at 10 years, and 24% at 20 years after diagnosis.
Diminutive polyp <5mm size reaches 1cm at 3yrs
Age distributions-mean age of people with a single adenoma
is about 4 to 5 years younger than those with a colon cancer.
A similar analysis in FAP patients has shown that patients with
adenomas are about 12 years younger than colon cancer.

38. Multiple Adenomas-2 or more
Synchronus adenoma– same time
(30%),50-85% 2 cancers
Metachronus lesion-6 months later

39. Initial treatment
Full colonoscopy
Remove Polyp
Histological examination
Search synchronous lesion
Complete endoscopic resection

40. A few general
recommendations
contain carcinoma in situ, pedunculated
adenomas that harbour well differentiated or
moderately differentiated invasive carcinoma,
and polypoid carcinomas.
Endoscopic polypectomy alone is adequate
therapy for adenomas that

41. malignant polyps in which the invasive carcinoma is
poorly differentiated,
involves endothelium-lined channels
(lymphatics,blood vessels),
extends to or within 2 mm of the polypectomy
margin,
or involves the submucosa of the colonic wall
(includes all sessile adenomas).
Resection surgery is indicated for

43. Polyp Recurrence Rates.

44. Surveillance Recommendations
after
Polypectomy

45. Serrated Polyps
Most common nonadenomatous polyps.
CpG island methylation pathway (CIMP) results in decreased
expression of genes,including DNA mismatch repair genes,
which can lead to microsatellite instability (MSI).
SSP/As are much less common than HPs, accounting for less
than 1% of all polyps and between1% and 11% of adenomas
SSP/As are typically flat, located in the right colon, and
covered with a mucus cap.

46. Features of Serrated Polyps

47. Treatment
It is recommended that all serrated polyps
be removed when detected.
This is because it may not be possible to
distinguish SSP/A or TSA from an HP, and
SSP/As and TSAs have a significant risk
of progression to invasive carcinoma.

48. Thank
you