Caption

Rectal polyp. Coloured scanning electron micrograph (SEM) of a polyp from the rectum, the last section of the large intestine. Polyps are usually benign growths (adenomas) that protrude from a mucous membrane. Most polyps are connected to the lining of the large intestine by a short stalk. As polyps can become cancerous, they are often surgically removed as a precautionary measure. Magnification unknown.