A rectal biopsy is a procedure to remove a small piece of rectal tissue for examination.
Biopsy - rectum
How the Test is Performed
A rectal biopsy is usually part of anoscopy or sigmoidoscopy.
A digital rectal exam is done first. Then, a lubricated instrument (anoscope or proctoscope) is placed into the rectum. You will feel some discomfort when this is done.
A biopsy can be taken through any of these instruments.
How to Prepare for the Test
You may get a laxative, enema, or other preparation before the biopsy so that you can completely empty your bowels. This will allow the doctor a clear view of the rectum.
How the Test Will Feel
There will be some discomfort during the procedure. You may feel like you need to have a bowel movement. You may feel cramping or mild discomfort as the instrument is placed into the rectal area.
Why the Test is Performed
A rectal biopsy is used to determine the cause of abnormal growths found during anoscopy, sigmoidoscopy, or other tests. It can also be used to confirm the diagnosis of amyloidosis.
The anus and rectum appear normal in size, color, and shape. There should be no evidence of bleeding, polyps, hemorrhoids, or other abnormalities. No problems are seen when the biopsy tissue is examined under a microscope.
What Abnormal Results Mean
This test is a common way to confirm amyloidosis. It also determines the specific causes of abnormal conditions of the rectum, such as colitis. Other findings could include:
- Colorectal polyps
The test may be also performed for:
- Crohn's disease
- Hirschsprung's disease in infants
- Ulcerative colitis
There is some risk of bleeding and tearing. Occasionally, patients may develop difficulty with urination after the procedure.
Reviewed By: Robert A. Cowles, MD, Associate Professor of Surgery, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, and Stephanie Slon.