Causes
By Mayo Clinic staffThe exact cause of fibrocystic breast changes isn't known, but experts suspect that reproductive hormones — especially estrogen — play a role.
If you aren't yet menopausal, your discomfort may result from the way your hormone levels fluctuate during your menstrual cycle. The fluctuations can make your breasts have areas of lumpy thickening that feel tender, sore and swollen. Those fibrocystic breast changes often feel the worst before your menstrual period, and the pain and lumpiness tends to clear up once your menstrual period begins.
When examined under a microscope, fibrocystic breast tissue includes distinct components such as:
- Fluid-filled round or oval sacs (cysts)
- A prominence of scar-like fibrous tissue (fibrosis)
- Overgrowth of cells (hyperplasia) lining the milk ducts or milk-producing tissues (lobules) of the breast
- Enlarged breast lobules (adenosis)
- Non-cancerous breast conditions. American Cancer Society. http://www.cancer.org/healthy/findcancerearly/womenshealth/non-cancerousbreastconditions/non-cancerous-breast-conditions-fibrocystic-changes. Accessed Feb. 14, 2013.
- McPhee SJ, et al. Current Medical Diagnosis & Treatment 2010. New York, N.Y.: McGraw-Hill Medical; 2010. http://www.accessmedicine.com/content.aspx?aID=8538. Accessed Feb. 14, 2013.
- Frequently asked questions. Gynecologic problems FAQ026. Benign breast problems and conditions. American College of Obstetricians and Gynecologists. http://www.acog.org/~/media/For%20Patients/faq026.pdf?dmc=1&ts=20130214T1505295029. Accessed Feb. 14, 2013.
- Golshan M, et al. Breast pain. http://www.uptodate.com/home. Accessed Feb. 14, 2013.
- Pruthi S, et al. Vitamin E and evening primrose oil for management of cyclical mastalgia: A randomized pilot study. Alternative Medicine Review. 2010;15:59.
- Understanding breast changes: A health guide for women. National Cancer Institute. http://www.cancer.gov/cancertopics/screening/understanding-breast-changes. Accessed Feb. 14, 2013.
- Ferrara A. Benign breast disease. Radiologic Technology. 2011;82:447M.
- Sabel MS. Breast masses and other common breast problems. http://www.uptodate.com/home. Accessed Feb. 14, 2013.
- Evening Primrose oil. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Feb. 14, 2013.
- Gallenberg MM (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 19, 2013.
- Pruthi S (expert opinion). Mayo Clinic. Rochester, Minn. Feb. 25, 2013.


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