Gastroenterology Consultants,SC: Diseases of the GI tract COLON POLYPS AND CANCER [<<back | list all>>] A polyp is a growth that occurs in the colon and other organs. These growths, or fleshy tumors, are shaped like a mushroom or a dome-like button, and occur on the inside lining of the colon. They may be as small as a tiny pea or larger than a plum. Colon polyps start out as benign tumors but in time may become malignant. The larger the polyp the more likely it is to contain cancer cells.