There are three main types of colon polyps:
- Hyperplastic. Hyperplastic polyps occur most often in the descending colon (on your left side) and rectum. They are usually less than one-fourth inch in diameter and noncancerous. Larger, right-sided hyperplastic polyps may become cancerous.
- Adenomatous (adenomas). There are three types of adenomatous polyps: villous, tubular and tubulovillous. Villous adenomas are more likely to become cancerous.
- Inflammatory. Inflammatory polyps usually result from ulcerative colitis and aren't a cancer risk.
Colon polyps also are classified by shape. Pedunculated polyps grow on fleshy stalks and resemble mushrooms or toes. Sessile polyps have broad bases.
Hereditary polyp disorders
Rarely, people inherit genetic mutations that cause colon polyps to form. If you have one of these genetic mutations, you are at much higher risk of developing colorectal cancer.
Screening and early detection can help prevent the development or spread of these cancers. Mayo Clinic patients in Minnesota are placed on a colorectal cancer prevention registry and updated on new screening techniques and procedures. Mayo researchers are working to discover more genetic mutations that cause hereditary polyp disorders.
Mayo Clinic specialists are experienced in treating these hereditary polyp disorders:
Hereditary nonpolyposis colon cancer (Lynch syndrome)
Familial adenomatous polyposis and its variations:
- Attenuated FAP
- Gardner syndrome
- Turcot syndrome
Hamartomatous polyposis syndromes, including:
- Juvenile polyposis. Polyps usually begin growing in early childhood. The risk of developing cancer of the colon ranges from 9 to 50 percent. Stomach cancer is also a risk.
- Peutz-Jeghers syndrome. In addition to polyps, freckles or dark spots appear on the lips, in the lining of the mouth and around the eyes. The risk of developing colon cancer is about 40 percent. People with Peutz-Jeghers are also at increased risk for breast, pancreas, stomach and ovarian cancers.
- Cowden's disease. People with Cowden's are at increased risk for breast and thyroid cancers, as well as colon polyps that may progress to colorectal cancer.
Read more about colon polyp types at MayoClinic.com.