Fibrocystic changes in the breast refer to a variety of irregularities in the breast tissue. These changes are benign, or noncancerous.

What is going on in the body?

Fibrocystic changes occur when there is an imbalance of the female hormones produced by the ovaries. These hormones are estrogen and progesterone. The imbalance changes breast tissue to produce lumps. This condition is very common and is not cancer.

What are the causes and risks of the condition?

Fibrocystic changes are caused by a hormonal imbalance. This imbalance usually involves estrogen and progesterone. An increase in another hormone, prolactin, may also be responsible for some of the changes. Over half of all women experience fibrocystic changes at some time in their lives. The changes are most common in women between the ages of 20 and 50. The condition is uncommon after menopause unless the woman is taking hormone replacement therapy.