21. Large Bowel Tumours

Question 1

What is a polyp?

Answer 1

Mass arising form mucosal epithelium or submucosa, protruding into the lumen

Question 2

What are the types of non-neoplastic polyps?

Answer 2

Hyperplastic
Hamartomatous (Juvenile and Peutz-Jehger)
Inflammatory
Lymphoid

Question 3

What are hyperplastic polyps?

Answer 3

Glands with goblet cells and serrated appearance
Due to delayed shedding of surface epithelium
Very common in people over 60

Question 4

What are juvenile polyps?

Answer 4

Hamartomatous malformations of bowel mucosa

Dilated glands and inflamed stroma

Question 5

What are juvenile polyps known as in adults?

Answer 5

Retention polyps

Question 6

What description is used for Peutz-Jegher polyps?

Answer 6

Christmas tree

Question 7

What is Peutz Jegher syndrome?

Answer 7

AD
Mucocutaneous pigmentation
Polyps throughout GIT
Increase risk of pancreas, breast, lung, ovary and uterine cancers

Question 8

What is Cowden syndrome?

Answer 8

AD: mutation in PTEN gene
Multiple hamartomatous polyps and skin tumours
Increased risk of thyroid and breast cancer

Question 9

What is Cronkhite Canada syndrome?

Answer 9

Hamartomatous polyps
Nail atrophy
Skin pigmentation

Question 10

What are inflammatory polyps?

Answer 10

Inflamed regenerative mucosa surrrounded by ulcerated tissue

Seen in IBD

Question 11

What are neoplastic polyps?

Answer 11

Proliferation of dysplastic epithelium
Precursor to carcinoma
Can be tubular, villous (higher risk) or tubulovillous

Question 12

What are the clinical features of neoplastic polyps?

Answer 12

Asymptomatic
Bleeding, iron deficiency anaemia
Protein loss
Obstruction

Question 13

What gene is mutated in FAP?

Answer 13

APC gene on 5q21

Question 14

What is the treatment for FAP?

Answer 14

Remove whole colon as 100% risk of carcinoma in 10-15 years

Question 15

Name 2 variations of FAP

Answer 15

Gardener’s

Turcot’s

Question 16

What is Gardener’s syndrome?

Answer 16

many benign tumours, abnormal teeth

Increased risk of duodenal and thyroid cancer

Question 17

What is Turcot’s syndrome?

Answer 17

Colorectal adenomatous polyps

Brain tumours

Question 18

What are the risk factors for colonic adenocarcinoma?

Answer 18

Adenomatous polyps
Hereditary syndromes (Lynch and FAP)
IBD
Diet, obesity, physical inactivity

Question 19

What are the features of colonic adenocarcinoma in Lynch syndrome?

Answer 19

No adenoma-carcionoma sequence (straight to carcinoma)

Usually right sided

Question 20

What are the differences between type 1 and 2 lynch syndrome?

Answer 20

1 is just increased risk of colon cancer

2 has an increased risk of colon cancer, and endometrial and ovarian

Question 21

What is lynch syndrome caused by?

Answer 21

Defect in mismatch repair genes

Question 22

What infection is associated with colonic carcinoma?

Answer 22

Strep bovis endocarditis

Question 23

What are the macroscopic features of right sided adenocarcinoma?

Answer 23

‘Cauliflower’ appearance

May ulcerate and bleed: iron deficiency anaemia

Question 24

What are the macroscopic features of left sided adenocarcinoma?

Answer 24

More likely to encircle the colon in a ‘napkin ring’ appearance
Causes constriction and obstruction as left sided lumen is narrow and faeces are more solid
Poorer prognosis

Question 25

What are the histological features of adenocarcinoma of the bowel?

Answer 25

Produce mucin Signet ring appearance (mucin) CEA marker

Question 26

Where is colonic carcinoma most likely to metastasise to?

Answer 26

Liver and Lungs

Question 27

What staging system is used for colonic adenocarcinoma?

Answer 27

Duke's staging

Question 28

Why are NSAIDs protective against colonic adenocarcinoma?

Answer 28

Reduce proliferation and angiogenesis | Increase apoptosis

Question 29

What are the targeted treatment options for colonic adenocarcinoma?

Answer 29

Cetuximab and panitumumab block EGFR signalling pathoway | Bevacizumab prevents angiogenesis

Question 30

What must be done before prescribing cetuximab?

Answer 30

Use PCR to make sure there is no mutation in k-ras or the patient will not respond to therapy

Question 31

Which organs metastasise to the colon?

Answer 31

Melanoma Ovary Endometrial Prostate

Question 32

Why does carcinoid syndrome only affect the right heart?

Answer 32

5-HT is broken down in the lung so never gets to the left heart

Question 33

Which cells do GISTs originate in?

Answer 33

Interstitial cells of Cajal

Question 34

What mutations are associated with GISTs?

Answer 34

Platelet Derived Growth Receptor a mutation | c-kit proto-oncogene

Question 35

Which therapy targets the c-kit oncogene?

Answer 35

Imatinib

Question 36

Is B or T cell lymphoma more common in the GIT?

Answer 36

B cell; all except EATL