– Any mass of tissue arising from the bowel wall and protruding into the lumen; the masses may be sessile or pedunculated and vary considerably in size.
Causes and Incidence
Polyps may be idiopathic or may be associated with an autosomal dominant trait (familial polyposis, Gardner’s syndrome) or underlying disease of the colon such as ulcerative colitis or Crohn’s disease. Incidence reports are highest in North America and Europe, and the disorder has been noted in as much as 50% of the population in the United States on autopsy. The likelihood of the disease increases with age.
Normal cell proliferation and differentiation processes are altered, causing a proliferation of immature epithelial cells that accumulate and form a tissue mass on the bowel wall. The predominant site of formation is the lower 25 cm of the colon, although the polyps may occur throughout the gastrointestinal tract.
Most polyps are asymptomatic. The most commonly reported symptom is rectal bleeding. Occasionally a large polyp causes cramps, abdominal pain or obstruction, or profuse, watery diarrhea.
Strong evidence suggests that adenomatous polyps may become malignant, particularly when large and when found in sizable clusters.
The diagnosis is made by rectal examination or endoscopy, or both.
Excision with wide margins for sessile polyps, adenomas, and cancerous lesions; prophylactic proctocolectomy with ileostomy for inherited multiple polyposis syndrome.
Polypectomy by colonoscopy for benign pedunculated polyps and juvenile polyps; follow-up evaluation with colonoscopy twice a year for 2 years, then every 2 years for life.