Colonic polypectomy. Endoscope view of a small benign (non-cancerous) polyp being surgically removed in the sigmoid colon (the final part of large intestine which joins the rectum). This polyp is a tubular adenoma, a tumour arising from the epithelial tissue lining an organ. If the polyp causes discomfort, for instance by obstructing the flow of food along the intestine, it is removed surgically. Some types of polyp may turn cancerous, and are removed as soon as they are discovered.