Polyps are abnormal growths of the mucus membranes and can occur anywhere in the body. Colon polyps grow on the mucus membranes (lining) of the large intestine. They are caused by heredity (inherited or familiar disorder), abnormal cell growth, or diseases such as Crohn's disease or ulcerative colitis. Symptoms of colon polyps may include blood in the bowel movement, pain or cramping in the abdomen, or fatigue. Polyps may be benign (not cancerous) or malignant (cancerous).
Pedunculated Polyp
If a polyp is attached to the mucous membrane with a narrow stalk of tissue it is called a pedunculated polyp.
Sessile Polyp
When the polyp grows directly on the mucous membrane and no stalk of tissue is present, the polyp is sessile.
Adenomatous Polyps
Adenomatous polyps develop in the lining of the colon, usually due to DNA changes. According to the College of American Pathologists, approximately 10 percent of these polyps become malignant (cancerous) within 10 years if not found early and removed. When multiple polyps are present, the chance that one will become malignant increases. As the polyp grows, the chance that it will become malignant increases. Adenomatous polyps can be subdivided into three kinds: tubular, tubulovillous, and villous.
Tubular Adenomatous Polyps
Tubular adenomatous polyps can be sessile or pedunculated. They are the most common type of adenomatous polyp and can be found anywhere in the colon.
Tubulovillous Adenomatous Polyps
These polyps are found most often in the distal colon and rectum. The greater the amount of villous component, the greater the chance of malignancy.
Villous Adenomatous Polyps
Villous adenomatous polyps usually occur in the rectum, but can occur elsewhere in the colon. They are generally large, non-pedunculated, and look like cauliflower. This is the worst type of colon polyp and is associated with a higher mortality and morbidity than others.
Hyperplastic Polyps
Hyperplastic polyps account for 20 to 30 percent of polyps and rarely become malignant. They are generally sessile, small, round and are made up of epithelial cells.
Inflammatory Polyps
Inflammatory polyps usually develop after an episode of Crohn's disease or ulcerative colitis. Although these polyps rarely cause problems, Crohn's disease and ulcerative colitis do increase the risk of colon cancer, according to the American Cancer Society.
Polyps Associated with Polyposis Syndromes
Polyps associated with polyposis syndromes usually become malignant. These polyps are most often seen in families with a history of colon polyps (familial adenomatous polyposis or hamartomatous familial polyposis), may occur in large numbers, and often occur in younger patients, according to the American Cancer Society.
