Most breast lumps are benign (non-cancerous), as in fibroadenoma, a condition that mostly affects women under age 30. Fibrocystic breast changes occur in more than 60% of all women. Fibrocystic breast cysts change in size with the menstrual cycle, whereas a lump from fibroadenoma does not. While most breast lumps are benign, it is important to identify those that are not. See your health care provider if a lump is new, persistent, growing, hard, immobile, or causing skin deformities.
Update Date 11/15/2013
Updated by: Debra G. Wechter, MD, FACS, General Surgery practice specializing in breast cancer, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.