A spontaneous growth of tissue which forms an abnormal mass is called a tumor. A tumor that is noninvasive and noncancerous is referred to as a benign tumor.
Review 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.