50. Colonic polyps Flashcards Preview

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Flashcards in 50. Colonic polyps Deck (21):
1

colonic polyps ?

frowth of tissue within the coln --> neoplastic or non- neoplastic

2

colonic polyps - gross appearance

flat, sessile , or pedunculated ( on a stalk ) on the basis of protrusion into colonic lumen

3

histological types ( neoplastic or not ?)

1. hyperplastic - non neoplastic
2. hamartomatous - non neoplastic
3. adenomatous - neoplastic
4. serrated - premalignant

4

cyperplastic - apperance and location

non- neoplastic generally smaller and majority located in RECTOSIGMOID area

5

Colonic polyps - hamartomatous - apperance

non- neoplastic . growth of normal colonic tissue with distorted architecture

6

hamartomatous - associated with .... malignant ?

associated with Peutz-Jegjers syndrome and juvenile polyposis
- solitary lesions do not have risk of malignant transformation

7

adenomatous - mechanism / presentation

chromosomal instability patheay with mutations in APC and KRAS. presentation : usually asymptomatic, may present with occult bleeding

8

adenomaatous - types and malignancy

tubular --> less malignant potential
villous --> more malignant potential
tubulovirous --> intermediate malignant potential

9

serrated - mechanism / biopsy

premalignant , via CpG hypermethylation phenotype pathway with microsatellite instability
biopsy: saw tooth pattern of crypts

10

serrated - malignancy

up to 20% of cases of sporadic colorectal cancer

11

microsatellite instability is the condition of

genetic hypermutability that results from impaired DNA mismatch repair ( MMR)

12

• A man has a biopsy of a colonic polyp. The more ____ (villous/sessile/tubular/hyperplastic) it is, the more likely that it is malignant.

Villous

13

• Your 50-year-old patient has a history of hyperplastic polyps. On colonoscopy, where do you most expect to find new hyperplastic polyps?

In the rectosigmoid area

14

• A child with rectal discomfort has a single rectal juvenile polyp on colonoscopy. He is otherwise well. Should be polyp be urgently removed?

No; there is no malignant potential if it is truly the only juvenile polyp

15

• The malignancy risk of adenomatous polyps is not associated with ____ (degree of dysplasia/villous histology/size/symptoms).

Symptoms

16

• What type of polyp is considered a precursor for colorectal cancer?

Adenomatous polyps

17

• List these three adenomatous polyp subtypes in order of their potential for malignant transformation, from lowest to highest.

Tubular adenomas, tubulovillous adenoma, villous adenomas

18

• What two conditions are associated with the formation of hamartomatous polyps?

Peutz-Jeghers syndrome and juvenile polyposis

19

• APC and KRAS, which are commonly mutated via the

chromosomal instability pathway in neoplastic polyps

20

• A patient has a colonoscopy. Polyps are biopsied, and "saw tooth" crypts are seen. Is there a risk of progression to colorectal cancer?

Yes, as the biopsy description is consistent with serrated polyps, which are premalignant (~20% of sporadic colorectal cancer cases)

21

• What genetic mutations are associated with serrated polyps?

The CpG hypermethylation phenotype pathway with microsatellite instability, and mutations in BRAF

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