Each of your breasts contains lobes of glandular tissue, arranged like petals of a daisy. The lobes are divided into smaller lobules that produce milk during pregnancy and breast-feeding. The supporting tissue that gives the breast its shape is made up of fatty tissue and fibrous connective tissue. Breast cysts develop as a result of fluid accumulation inside the glands in the breasts.
Breast cysts may be defined by their size:
- Microcysts are too small to feel, but may be seen during imaging tests, such as mammography or ultrasound.
- Macrocysts are large enough to be felt and can grow to about 1 to 2 inches (2.5 to 5 centimeters) in diameter. Large breast cysts can put pressure on nearby breast tissue, causing breast pain or discomfort.
Experts don't know what causes breast cysts. They may develop as a result of hormonal changes from monthly menstruation. Some evidence suggests that excess estrogen in your body, which can stimulate the breast tissue, may contribute to breast cysts.
Oct. 08, 2015
- Non-cancerous breast conditions. American Cancer Society. http://www.cancer.org/docroot/CRI/content/CRI_2_6X_Non_Cancerous_Breast_Conditions_59.asp?sitearea. Accessed July 15, 2015.
- Golshan M, et al. Breast pain. http://www.uptodate.com/home. Accessed July 15, 2015.
- Salzman B, et al. Common breast problems. American Family Physician. 2012;86:343.
- Evening primrose oil. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Aug. 2, 2015.
- Understanding breast changes: A health guide for women. National Cancer Institute. http://www.cancer.gov/cancertopics/screening/understanding-breast-changes. Accessed July 15, 2015.
- Laronga C, et al. Breast cysts: Clinical manifestations, diagnosis and management. http://www.uptodate.com/home. Accessed July 15, 2015.
- Pruthi S (expert opinion). Mayo Clinic, Rochester, Minn. Aug. 17, 2015.
- Ferrara A. Benign breast disease. Radiologic Technology. 2011;82:447M.
- Evening primrose oil. Bethesda, Md. National Center for Complementary and Integrative Health. https://nccih.nih.gov/health/eveningprimrose. Accessed Aug. 2, 2015.