Lower GI Neoplasms

Question 1

what is the most common malignancy of the small bowel?

Answer 1

carcinoid tumor

Question 2

what type of tissue are carcinoid tumors derived from?

Answer 2

neuroendocrine cells

Question 3

how do carcinoid tumors of the SI present usually?

Answer 3

asymptomatic

Question 4

what two things can carcinoid tumors of the SI cause that are problematic?

Answer 4

obstruction and intussusception

Question 5

what is a common location for carcinoid tumors of SI to metastasize? why?

Answer 5

liver because they are drained by the superior mesenteric vein

Question 6

what are the symptoms of a carcinoid tumor of the SI if it has metastasized to the liver?

Answer 6

flushing
wheezing
hypotension

Question 7

where is another location for carcinoid tumors to occur in the GI tract

Answer 7

appendix tip

Question 8

how do carcinoid tumors appear histologically?

Answer 8

bland tumor cells with salt and pepper chromatin

Question 9

what is a special chemical stain for neuroendocrine cells that lights up red in carcinoid tumors?

Answer 9

synaptophysin

Question 10

what is the non malignany safest polyp to have in the colon?

Answer 10

hyperplastic polyp

Question 11

how do hyperplastic polyps appear grossly? size?

Answer 11

pale epithelial sessile polyp

less than 3 mm

Question 12

on histo…what do hyperplastic polyps have in them?

Answer 12

serrated/convoluted appearance of the crypts with lots of goblet cells

Question 13

what is the premalignant type polyp of the colon?

Answer 13

colonic adenomas

Question 14

are colonic adenomas metaplastic, dysplastic or malignant?

Answer 14

always dyplastic

Question 15

what is the usual thing colon cancer arises from?

Answer 15

colonic adenomas

Question 16

name the two gene hits that lead to precancerous adenomas

Answer 16

APC and RAS

Question 17

describe the two growth patterns for polyps

Answer 17

sessile. ..grows in place and is mainly attached to wall

pedunculated. ..grows off wall with a stalk

Question 18

which growth pattern is better, sessile or pedunculated for polyps?

Answer 18

pedunculated because easier to remove

Question 19

what are the three histo architectures of polyps?

Answer 19

tubular
vilous
tubulovillous-mix of first two

Question 20

describe the tubular polyp architecture

Answer 20

adenomatous epithelium arranged in closely packed branching tubules having a cerebriform pattern at low power

Question 21

describe the vilous architecture of polyps

Answer 21

adenomatous epithelium forms traight elongated finger like projections extending from muscularis mucosae to luminal surface

Question 22

how do the nuclei of adenomatous epithelium of colonic polyps change from normal?

Answer 22

pleomorphic with hyperchromatic nuclei…lose mucin ( less goblet cells)`

Question 23

what is the usual cause of colorectal cancer?

Answer 23

invasive carcinoma from malignant polyps

Question 24

if you have early invasive carcinomas with a malignant polyp then what must you do?

Answer 24

surgically resect

Question 25

what are the five worrisome types of presentation for colon cancer?

Answer 25

obstruction 
bleeding
weight loss
change in bowel habits (thin stool)
iron deficiency anemia

Question 26

if there is iron deficiency anemia and you suspect colon cancer what must be done? what is not sufficient?

Answer 26

must do colonoscopy…fecal occult blood testing is not sufficient

Question 27

what is the usual shape/appearance of tumors in the right colon?

Answer 27

polypoid or fungating exophytic masses

Question 28

what is the usual shape/appearnace of tumors in the left colon?

Answer 28

apple core or napkin ring appearance with bowel obstruction

Question 29

what are three things that contribute to prognosis for colon cancer?

Answer 29

degree of differentiation
extent of bowel penetration
nodal involvement

Question 30

what is peutz jehgers syndrome? how is it inherited? what is mutation?

Answer 30

germline mutation in STK11 gene

autosomal dominant

Question 31

what are two signs of peutz jehgers syndrome?

Answer 31

pigmented spots on lips and buccal mucosa

multiple GI hamartomatous polyps