Polyps are tissue growths that most often look like small, flat bumps or tiny mushroom-like stalks. They are usually small and less than half an inch wide. Most are benign but can become cancerous.

A polyp is a growth inside of your body that contains malignant (cancerous) or cells that may become malignant. It’s a clump of cells that are growing abnormally. A polyp is usually shaped one of two ways. It can be a flat bump (sessile). Or it can be shaped like a mushroom, with a bulbous head projecting from a stalk (pedunculated).

A polyp of the colon refers to a protuberance into the lumen above the surrounding colonic mucosa. Colon polyps are usually asymptomatic but may ulcerate and bleed, cause tenesmus if in the rectum, and, when very large, produce intestinal obstruction. Colonic polyps may be neoplastic (eg, adenomas) or non-neoplastic (eg, inflammatory polyps).

There are two main categories of polyps, nonneoplastic and neoplastic. Nonneoplastic polyps typically do not become cancerous. Neoplastic polyps include adenomas and serrated types. Adenomas are the most likely to turn into cancer if given enough time to grow. Serrated polyps also may become cancerous, depending on their size and location.