Which of the following is a premalignant condition for colorectal carcinomas?
|A||Villous adenoma (Villous papilloma)|
|C||Peutz jeghers polyps|
a. A colorectal polyp is any mass projecting into the lumen of the bowel above the surface of the intestinal epithelium.
b. Polyps arising from the intestinal mucosa are generally classified by their gross appearance as pedunculated (with a stalk) or sessile (flat, without a stalk) .
c. They are further classified by their histologic appearance as tubular adenoma (with branched tubular glands), villous adenoma (with long finger-like projections of the surface epithelium), or tubulovillous adenoma (with elements of both cellular patterns).
d. The most common benign polyp is the tubular adenoma, constituting about 65% to 80% of all polyps removed.
e. About 10% to 25% of polyps are tubulovillous, and 5% to 10% are villous adenomas.
f. Tubular adenomas are most often pedunculated; villous adenomas are more commonly sessile.
g. The degree of cellular atypia is variable across the span of polyps, but there is generally less atypia in tubular adenomas, and severe atypia or dysplasia (precancerous cellular change) is found more often in villous adenomas.
h. There is less than a 5% incidence of carcinoma in an adenomatous polyp less than 1 cm in size, whereas there is a 50% chance that a villous adenoma greater than 2 cm in size will contain a cancer.
i. The treatment of an adenomatous or villous polyp is removal, usually by colonoscopy.
j. The presence of any polypoid lesion is an indication for a complete colonoscopy and polypectomy, if feasible.