Pathology of Colon

Question 1

What gene mutations are associated with ulcerative colitis and Crohn’s disease?

Answer 1

Ulcerative colitis- HLA

Crohn’s disease- NOD2

Question 2

What causes ischaemic enteritis?

Answer 2

Acute collusion of any or all of the three main arteries supplying the gut tube

Question 3

What are the predisposing conditions for ischaemic enteritis?

Answer 3

Arterial thrombosis
Arterial embolism
Non-occlusive ischaemia

Question 4

Where in the GI tract is most vulnerable to acute ischaemia?

Answer 4

The splenic flexure

Question 5

What are the histological characteristics of acute ischaemia?

Answer 5

Oedema
Interstitial haemorrhages
Sloughing necrosis of mucosa-ghost outlines
Nuclei indistinct
Initial absence of inflammation
1-4 days –bacteria-gangrene and perforation
Vascular dilatation

Question 6

What are the characteristics of chronic ischaemia?

Answer 6

Mucosal inflammation
Ulceration
Submucosal inflammation
Fibrosis
Stricture

Question 7

What causes radiation colitis?

Answer 7

Rectum-pelvic radiotherapy

Question 8

What are the symptoms of radiation colitis?

Answer 8

Anorexia
Abdominal cramps
Diarrhoea
Malabsorption

Question 9

What are the histological characteristics of radiation colitis?

Answer 9

Bizarre cellular changes
Inflammation-crypt abscesses and eosinophils
Later-arterial stenosis
Ulceration
Necrosis
Haemorrhage
Perforation

Question 10

What are the histological characteristics of appendicitis?

Answer 10

Macro- fibrinopurulent exudate, perforation, abscess
Micro-
Acute suppurative inflammation in wall and pus in lumen
Acute gangrenous-full thickness necrosis +/- perforation

Question 11

What are the histological characteristics of large bowel adenoma?

Answer 11

Low grade dysplasia
Increased nuclear nos.
Increased nuclear size
Reduced mucin

High grade dysplasia
Carcinoma in situ
Crowded
Very irregular
Not yet invasive