Colon polyp. Virtual colonoscopy (VC) image of a colon polyp in a 54-year-old patient. A VC is constructed from 3D CT (computed tomography) scans, which are completely non-invasive. At centre is a pedunculate (stalked) polyp in the colon at the lower part of the large intestine. Such polyps are benign (non-cancerous) growths that arise from the lining of the colon. Although benign, polyps are generally removed surgically as their growth may obstruct the passage of food, and some polyps do turn cancerous over time.