Polyposis of the small intestine, illustration. Polyps (shown at lower left inside the intestine) are benign growths. They can be flat (sessile) or on a stalk (pedunculated). If they turn cancerous, or grow large enough to obstruct the colon, they are surgically removed. At upper right, the (normal) layers of the intestinal wall are shown, including the mucosa, muscles and blood vessels.