Colon polyps are small fleshy growths of tissue that from the tissue lining the intestinal tract. Polyps generally cause no symptoms and do no harm unless they turn cancerous. Most polyps are detected and removed during a routine screening procedure known as colonoscopy. Some people have a higher chance of developing polyps due to hereditary or lifestyle issues.
Cause
Polyps occur when cells grow abnormally, continuing to divide even when new cells aren't needed in an area of the intestine. Colon cells continue dividing due to changes in the genes that control cell division; the abnormal cells eventually form polyps. Polyps can be flat, called sessile, or on a stalk, called pedunculated. Flat, large polyps are most likely to turn cancerous.
Risk Factors
Most polyps develop in people over age 50. Risk factors for developing polyps include an inactive lifestyle, a diet high in fat, a family history of polyps and being overweight. African Americans and Ashkenazi Jews have a higher risk of developing polyps. People who drink excessively, especially beer, and smokers are also prone to developing polyps, MayoClinic.com reports. A number of rare genetic disorders can also cause multiple polyp formation.
Location
Polyps grow in the colorectal part of the intestine. The colon, or large intestine, consists of three sections: the ascending colon, found on the right side of the body; the transverse, which goes straight across the abdomen; and the descending colon, found on the left. The colon connects to the small intestine at one end and the rectum at the other. If stretched out, the colon would be between 4 to 6-feet long. The rectum comprises the last 8 to 12 inches of the intestinal tract. Most polyps that turn cancerous occur in the rectum and the sigmoid colon, the last part of the large intestine, the Merck Manual explains.
Types
Polyps can grow from different types of tissue. Around 66 percent of polyps are adenomatous, according to MayoClinic.com, meaning that they grow from the tissue that lines the large intestine. Around 95 percent of polyps that turn cancerous fall into this category, the Merck Manual states. Hyperplastic polyps usually occur on the left or descending colon. Hyperplastic polyps usually don't become cancerous. Inflammatory polyps grow in people with diseases that cause inflammation of the colon such as Crohn's disease or ulcerative colitis.
Symptoms
While polyps often have no symptoms, they can cause bright red rectal bleeding, constipation or diarrhea.
Treatment
Small polyps are easily removed during a colonoscopy. Examination under a microscope determines whether or not a polyp is cancerous.
