Fibrocystic breast disease, commonly called fibrocystic breasts or fibrocystic change, is a benign (noncancerous) condition in which a woman has painful lumps in her breasts. Fibrocystic breast disease isn’t dangerous, but it can be a bothersome condition because it can cause discomfort. The condition is common. Although it isn’t dangerous to have fibrocystic breasts, this condition can make the detection of breast cancer more challenging. The exact cause of the condition is not known. Hormones made in the ovaries may make a woman's breasts feel swollen, lumpy, or painful before or during menstruation each month. Up to half of women have this condition at some time during their life. It is most common between the ages of 20 and 45. It is rare in women after menopause, unless they are taking estrogen.