Colorectal Pathology

Question 1

What benign polyps can arise in the large bowel?

Answer 1

FROM EPITHELIUM

• adenomas
• polyps from inflammatory disease
• hamartomas (juvenile polyp, Peutz-Jeghers)

FROM MESENCHYMA

• lipoma
• lymphangioma
• haemangioma
• fibroma
• leiomyoma

Question 2

What malignant polyps can arise in the large bowel?

Answer 2

• polypoid adenocarcinomas
• carcinoid polyps
• sarcomas
• lymphomatous polyps

Question 3

Describe the different macroscopic shapes of polyps in the large bowel?

Answer 3

• pedunculated
• sessile
• flat

Question 4

The microscopic architecture of adenomas can vary in the bowel. GIve examples of how they can appear on histology?

Answer 4

• Tubular
• Villous
• Mixture of both => Tubullovillous

Question 5

All adenomas are dysplastic. TRUE/FALSE?

Answer 5

TRUE

Question 6

All adenomas must be removed. TRUE/FALSE?

Answer 6

TRUE

- premalignant => can transform into adenocarcinoma

Question 7

How do colorectal tumours appear macroscopically?

Answer 7

ulcerating and stricturing mass

Question 8

What types of fat can colorectal tumours invade locally?

Answer 8

• pericolic fat

- serosal fat

Question 9

Describe the Duke staging of colorectal cancer

Answer 9

Dukes A: Confined by muscularis propria

Dukes B: Through muscularis propria

Dukes C: Metastatic to lymph nodes

Question 10

Compare the prognosis of each Duke’s staging using 5 year survival?

Answer 10

A - 90%
B - 70%
C - 35%

Question 11

Do colorectal carcinomas more commonly appear on the RIGHT or LEFT side of the large bowel?

Answer 11

75% Left sided (rectum, sigmoid, descending)

25% Right sided (Caecum, Ascending)

Question 12

What are the common presenting complaints when patients have a left sided colorectal cancer?

Answer 12

Blood PR
Altered bowel habit
Obstruction

Question 13

What are the common presenting complaints of a right sided colorectal cancer?

Answer 13

Anaemia

Weight loss

Question 14

Colorectal cancers commonly metastasise to what organ?

Answer 14

Liver

Question 15

What inherited syndromes can cause colorectal cancers?

Answer 15

Heriditary Non Polyposis Colorectal Cancer (HNPCC)
<100 polyps usually present

Familial Adenomatous Polyposis (FAP)
>100 polyps present

Question 16

When does HNPCC usually present and what genetic mutations cause this?

Answer 16

• Late onset
• Autosomal dominant
• Defect in DNA mismatch repair
• Mutation in MLH-1, MSH-2, PMS-1 or MSH-6 genes

Question 17

When does FAP usually present and what genetic mutations cause this?

Answer 17

• Early onset
• Autosomal dominant
• Defect in tumour supression
• Inherited mutation in FAP gene

Question 18

Tumours related to HNPCC commonly occur on the RHS of the colon. TRUE/FALSE?

Answer 18

TRUE

- tumour related to FAP occur throughout the colon in comparison

Question 19

What type of tumours occur in HNPCC and what other cancers is the condition linked to?

Answer 19

• Mucinous tumours

- Assoc. with gastric and endometrial carcinoma

Question 20

FAP is associated with what other cancers?

Answer 20

• desmoid tumours

- thyroid carcinoma

Question 21

An inflammatory response is seen in HNPCC but not FAP. TRUE/FALSE?

Answer 21

TRUE

- similar to inflammation in Crohn’s disease