Fibrocystic change occurs in up to 90% of women to a varying degree. It was previously known as fibrocystic disease but as it is a normal variant, is no longer considered to be a disease. It is an exaggerated response of the breast tissue to hormones and growth factors circulating in the body. This results in the formation of both small and large cysts, increased amounts of fibrous tissue and on a microscopic level, changes in the cells.
Fibrocystic change can cause breast pain, lumpiness and tenderness. Because the tissue is dense and lumpy it can make both examination by your doctor and imaging difficult to interpret. Fibrocystic change is considered part of normal variation of the breast tissue and does not increase the risk of breast cancer.