Colorectal 1 (648-658)

Question 1

Define a colonic polyp;

Answer 1

A proturusion of the mucosal surface or gorwth in bowel mucosa

Question 2

Name some types of colonic polyps;

Answer 2

Polyps from mucosa- adenomatous (tubular 80%, villous 10%, tubovillous 10%), or non-neoplastic (hyperplastic and juvenile). Polyps can be described as serrated (flat) or puductulated (stalk) or depressed.

Question 3

How are colonic polyps classified?;

Answer 3

Premalignant- adenomatous (tubovillous [high risk maligancy], tubular [lower risk of malignancy], villous [some risk of malignancy]. Non-malignant- hyperplastic (pseudopolyps e.g in IBD), juvenile (benign hamatomas). (serrated with high garde dysplasia is high risk for maligancy)

Question 4

Which colonic polyps have a pre-malignant potential?;

Answer 4

Adenomatous- tubovillous, villous, tubular.

Question 5

Which colonic polyp has the greatest risk of mlaignant transformation?;

Answer 5

Tubovillous. (Appearance of sessile polyp with dysplasia has higher risk malignant transformation)

Question 6

What is the difference between an adenoma and a carcinoma?;

Answer 6

Adenoma- benign tumour of glandular tissue.
Carcinoma- malignant tumour of epithelial cells.

Question 7

What is the difference between defintion of sarcoma, adenoma , adenocarcinoma and squamous cell carcinoma?;

Answer 7

Sacaroma- malignant tumour of connective tissue (bone cartalige, fat etc.) Adenoma- benign tumour of glandular tissue. Adenocarcinoma- malignant tumour of glandular tissue. Squamous cell carcinoma- malignant tumour of squamous cells.

Question 8

How would you risk stratify colorectal adenomas?;

Answer 8

Low risk- 1-2 polyps. Intermediate risk- 3-4 polyps (at least one >1cm). High risk- 5 polyps or more (at least one >1cm).

Question 9

How would you further manage patients with adenomas?;

Answer 9

Usually Remove polyps using either- Polypectomy- cold or hot snare (risk performation with hot) or endoscopic muscola resection. OR conservative (if patient not fit enough or declines)- keep under survillence.

Question 10

How would you further investigate a patient with colonscopy polypectomy biopsy showing moderately differentiated adenocarcinoma?;

Answer 10

Bloods- FBC, U&Es, LFTs, coagulation. Imaging- US liver +/- CT staging (if involving rectum needs MRI rectum). Keep under survalience with colonscopies.

Question 11

Describe the adenoma-carcinoma sequence;

Answer 11

Stepwise progression of mutational activation of onogenes (e.g. K-ras) and inactivation of tumour suppressor genes (e.g. p53) that results in cancer.