POLYPS 1

Epithelial tumors of the intestines:
major cause of morbidity and mortality worldwide

Colon, including rectum:
host to more primary neoplasms than any other organ in the body

Non-neoplastic Polyps

Hyperplastic polyps

Hamartomatous polyps

Juvenile polyps

Peutz-Jeghers polyps

Inflammatory polyps

Lymphoid polyps

Neoplastic Epithelial Lesions

Benign polyps

Adenomas

Malignant lesions

Adenocarcinoma

Squamous cell carcinoma of the anus

Other Tumors

Gastrointestinal stromal tumors

Carcinoid tumor

Lymphoma

lThe term polyp of the colon refers to a protuberance into the lumen from the normally flat colonic mucosa.

l

lPolyps are usually asymptomatic but may ulcerate and bleed, cause tenesmus if in the rectum, and, when very large, produce intestinal obstruction.

 lColonic polyps, or adenomas, are benign epithelial neoplasms that arise from the epithelial cells lining the colon.

lPolyps are traditionally divided into 4 groups.

lHyperplastic polyps.

lAdenomas.

lPolyposis syndromes.

lMiscellaneous.

lHyperplastic polyps comprise about 90% of all polyps and are totally benign protrusions.

lThey are usually less than 0.5 cm in diameter.

lThey most commonly occur in the rectosigmoid region during adulthood.

The lesions tend to be smaller than adenomas and do not appear to be related to the adenoma-carcinoma sequence.

lAdenomas comprise approximately 10% of polyps.

lMost (~90%) are small, usually less than 1.5 cm in diameter, and have a very small potential for malignancy.

lThe remaining 10% of adenomas are larger than 1.5 cm and have about a 10% chance of containing invasive cancer.

lAdenomas are traditionally divided into 3 types: tubular, tubulovillous, and villous.

lTubular adenomas are the most common of the 3 types and can be found anywhere in the colon.

lThose with a distinct stalk are termed pedunculated; those without a stalk are termed sessile.

lThe risk of progression to carcinoma is related to the size of the adenoma.

lTubulovillous adenomas are most commonly found in the rectal area.

lThe degree of villous component of these adenomas is correlated with the risk of progression to carcinoma.

lVillous adenomas most commonly occur in the rectal area.

lThey tend to be larger than the other two types; and tend to be nonpedunculated, velvety, or cauliflower-like in appearance.

lVillous adenomas are associated with the highest morbidity and mortality rates of all polyps.

lThey can cause hypersecretory syndromes characterized by hypokalemia and profuse mucous discharge and can harbor carcinoma in situ or invasive carcinoma more frequently than other adenomas.