"Benign" refers to a condition, tumor, or growth that is not cancerous. This means that it does not spread to other parts of the body. It does not invade nearby tissue. Sometimes, a condition is called benign to suggest it is not dangerous or serious.
In general, a benign tumor grows slowly and is not harmful. However, this is not always the case.
A benign tumor may grow big enough or be found near blood vessels, the brain, nerves, or organs. As a result, it can cause problems without spreading to another part of the body. Sometimes, these problems can be serious.
The opposite of benign is malignant.
Update Date 2/8/2015
Updated by: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.