Pathology of Lower GI

Question 1

What is inflammatory diarrhea

Answer 1

Diarrhea containing red/white cells and debris (maybe mucus)
Requires microscopic examination
Associated with inflammation of the colorectum

Question 2

3 causes of colitis

Answer 2

Infection
Inflammatory bowel disease
Ischemic colitis

Question 3

Indeterminate type inflammatory bowel disease

Answer 3

When its not possible to differentiate between Crohn’s and Ulcerative Colitis

Question 4

Crohn’s Disease

Answer 4

Any part of the GI tract
Patchy distribution
Transmural inflammation with associated serositis (can get stenosis or fistular tracts)
Granulomas (chronic inflammation, so can see the presence of epitheliod macrophages arranged in a group, ringed by lymphocytes)

Question 5

Ulcerative colitis

Answer 5

Colon only (starts in rectum and then moves proximal)
Continuous involvement
Inflammation limited to the mucosa
No granulomas

Question 6

4 complications associated with Crohn’s

Answer 6

Fistula tracts
Stenosis and obstruction (can get cobblestone appearance)
Dysplasia and carcinoma
Extraintestinal features (arthritis, eye lesions, skin lesions)

Question 7

3 complications with ulcerative colitis

Answer 7

Toxic megacolon (rare)
Dysplasia and carcinoma
Extraintestinal features (arthritis, eye lesions, skin lesions)

Question 8

2 histological changes in ulcerative colitis

Answer 8

Absence of goblet cells

Crypt distortion and abscess

Question 9

Microscopic colitis

Answer 9

When the colonoscopy is normal but the mucosal biopsy is abnormal
2 types: lymphocytic and collagenous
Present with chronic, watery, non-bloody diarrhea
More common in women

Question 10

Diverticular disease of the colon

Answer 10

Presence of multiple diverticula
Usually on the left side of the colon that may be associated with clinical findings
From high intraluminal pressure
Risk factors include low-fiber diet, inactivity, obesity, muscle wall weakness

Question 11

What are diverticula

Answer 11

Out pouchings of the wall of a hollow organ

Contain all layers of the wayy

Question 12

What are pseudodiverticula? Where are they found?

Answer 12

Colon diverticula are pseudodiverticula because they do not contain all layers of the bowel wall
Not rectum, found in distal colon

Question 13

3 complications of diverticulosis

Answer 13

Diverticulitis (erosion of the wall, may be associated with abscess, obstruction, perforation)
Bleeding
Diverticular disease associated colitis

Question 14

Colorectal polyps

Answer 14

A polyp is an abnormal growth of tissue projecting from a mucus membrane
Can be found in the colon or rectum
Can be neoplastic or non-neoplastic (not pre-malignant)

Question 15

Sessile vs pedunculated polyps

Answer 15

Sessile: broad base (plateau)
Pedunculated: has a stalk

Question 16

Hamartoma

Answer 16

Collection of tissue in an organ that is normally found in that organ, but in an excessive amount
Increase in epithelium, CT and smooth muscle

Question 17

Colorectal adenoma (what is it, 4 types)

Answer 17

Epithelial neoplasm that has the potential to progress to carcinoma
Pre-malignant neoplasm
Can be tubular, villous, tubulovillous, or serrated

Question 18

What adenomas are at highest risk to progress to carcinoma? (4 things)

Answer 18

Size > 1 cm
Presence of high grade dysplasia
Villous architecture
Serrated polyp

Question 19

In the colorectum only, when does invasive carcinoma begin?

Answer 19

When the cancer invades into the submucosa (through the muscularis mucosae)

Question 20

The majority of colorectal carcinomas are what type of cancer?

Answer 20

Adenocarcinoma

Question 21

Pathogenesis of acute appendicitis

Answer 21

Lumenal obstruction
Bacterial overgrowth
Inflammation/swelling (increased pressure)
Localized ischemia
Perforation
Peritonitis or abscess formation

Question 22

What is the most common neoplasm of appendix

Answer 22

Neuroendocrine tumor (carcinoid tumor)
Produces serotonin
Relatively benign, but may metastasize

Question 23

Carcinoid syndrome

Answer 23

Flushing, diarrhea, and wheezing
May occur in carcinoid tumor metastasis to the liver
Serotonin released into the systemic circulation

Question 24

How do people with microscopic colitis usually present?

Answer 24

Present with chronic, watery, non-bloody diarrhea

Question 25

What does a neuroendocrine tumor of the appendix (carcinoid tumor) secrete?

Answer 25

Serotonin