Polyps of the Colon and Rectum

Reviewed/Revised Jan 2023
VIEW PROFESSIONAL VERSION
Get the full details

What is a polyp of the colon or rectum?

A polyp is a round, smooth growth inside a hollow space in your body. For example, you may have polyps in your nose or on your vocal cords.

Your colon is your large intestine. Your rectum is a pouch at the end of your colon where stool is stored until you pass it. Polyps often grow in your colon (large intestine) or your rectum.

Locating the Large Intestine

  • You may have one polyp or a large number of them

  • Colon polyps are often harmless, but some are cancerous or may become cancerous

  • Certain conditions that run in families can cause polyps

  • Polyps may grow on a stalk (a thin stem that joins the polyp to the intestinal wall)

  • The larger the polyp, the greater the chance it's cancerous

  • Polyps may cause bleeding from your rectum

  • Doctors check for polyps with a colonoscopy

  • Doctors treat polyps by removing them

Polyps that are initially harmless can develop into colon cancer, which is why doctors remove them during a colonoscopy.

What causes polyps of the colon or rectum?

Most of the time, doctors don't know what causes a polyp to grow. But certain conditions that run in families can cause polyps, such as:

  • Familial adenomatous polyposis (a disease that runs in families and causes colon cancer)

  • Peutz-Jeghers syndrome (a disease that causes polyps in your stomach and intestines and blue and black spots on your face, hands, and feet)

However, these conditions are uncommon. Most often, polyps just form for no clear reason.

What are the symptoms of polyps of the colon or rectum?

Most polyps don't cause symptoms. The most common symptom is bleeding from your rectum. A large polyp may cause:

  • Cramps

  • Belly pain

  • Intestine problems, such as a blockage

  • Diarrhea

How can doctors tell if I have polyps of the colon or rectum?

Doctors find polyps with sigmoidoscopy or colonoscopy (see endoscopy). With both of these tests, the doctor threads a thin, lighted tube with a small camera through your anus to look at the inside of your rectum and colon.

How do doctors treat polyps of the colon or rectum?

Doctors remove polyps during sigmoidoscopy or colonoscopy. Inside the viewing tube is a retractable tool that can snip off the polyp. Sometimes, surgery is needed. If a polyp is cancerous, doctors will run other tests to see how likely it is to have spread. You may need surgery to take out part of your intestine.

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID