Pathology of the Colorectal Carcinoma

Question 1

Define a polyp

Answer 1

A polyp is a protrusion above the epithelial surface

Question 2

Give examples of different colonic polyps

Answer 2

Adenoma
Serrated polyps
Polypoid carcinoma

Question 3

Describe the histopathology of dysplastic polyps

Answer 3

A polyp with a dysplastic lining is an adenoma of the colon. These are benign, non-invasive tumours with large nuclei

Question 4

Outline the pathophysiology of an adenocarcinoma

Answer 4

Normal mucosa → Adenoma (dysplastic) → Adenocarcinoma (invasive)

Question 5

How and why are adenomas removed?

Answer 5

Adenomas are removed endoscopically or surgically. They are removed as all adenomas are pre-malignant

Question 6

Outline the different stages of Duke’s staging

Answer 6

Dukes A - confined within muscularis propria
Dukes B - through muscularis propria
Dukes C - Metastasised to lymph nodes

Question 7

Describe the different presenting complaints of colorectal cancer

Answer 7

75% of colorectal carcinomas are left-sided and present as blood PR, altered bowel habit and obstruction
The remaining 25% are right sided and present as anaemia and weight loss

Question 8

Describe the appearance of colorectal carcinoma

Answer 8

Colorectal carcinomas have a varied gross appearance but a very typical histopathological appearance

Question 9

What are the different patterns of spread of colorectal carcinoma?

Answer 9

Locally - mesorectum, peritoneum, other organs
Lymphatically - mesenteric nodes
Haematogenously - liver, distant sites

Question 10

What are the two inherited cancer syndromes in the colorectum?

Answer 10

Hereditary Non-Polyposis Coli (HNPCC)

Familial Adenomatous Polyposis (FAP)