gastrointestinal disorders
Polyps of the Colon and Rectum
Introduction
An intestinal polyp is any mass of tissue that arises from the bowel wall and protrudes into the lumen. Most are asymptomatic except for minor bleeding, which is usually occult. The main concern is malignant transformation; most Colorectal Cancer arise in a previously benign adenomatous polyp. Diagnosis is by endoscopy. Treatment is endoscopic removal. Polyps may be sessile or pedunculated and vary considerably in size. Incidence of polyps ranges from 7 to 50%; the higher figure includes very small polyps (usually hyperplastic polyps or adenomas) found at autopsy. Polyps, often multiple, occur most commonly in the rectum and sigmoid and decrease in frequency toward the cecum. Multiple polyps may represent Familial Adenomatous Polyposis . About 25% of patients with cancer of the large bowel also have satellite adenomatous polyps. Adenomatous (neoplastic) polypsare of greatest concern. Such lesions are classified histologically as tubular adenomas, tubulovillous adenomas (villoglandular polyps), or villous adenomas. The likelihood of cancer in an adenomatous polyp at the time of discovery is related to size, histologic type, and degree of dysplasia; a 1.5-cm tubular adenoma has a 2% risk of containing a cancer vs a 35% risk in 3-cm villous adenomas. Serrated adenomas, a somewhat more aggressive type of adenoma, may develop from hyperplastic polyps. include hyperplastic polyps, hamartomas (see Peutz-Jeghers Syndrome ), juvenile polyps, pseudopolyps, lipomas, leiomyomas, and other rarer tumors. Juvenile polyps occur in children, typically outgrow their blood supply, and autoamputate some time during or after puberty. Treatment is required only for uncontrollable bleeding or intussusception. Inflammatory polyps and pseudopolyps occur in chronic This image shows a sessile, multilobulated polyp, which, on biopsy, turned out to be a benign tubular adenoma. Image provided by David M. Martin, MD. This image shows a pedunculated polyp, which, on biopsy, turned out to be a benign tubular adenoma. Image provided by David M. Martin, MD. This image shows a sessile polyp, which, on biopsy, turned out to be a tubulovillous adenoma. Image provided by David M. Martin, MD. 