The pathophysiology of fibrocystic breast disease is determined by estrogen predominance and progesterone deficiency that result in hyperproliferation of connective tissue (fibrosis), which is followed by facultative epithelial proliferation; the risk of breast cancer is increased twofold to fourfold in these patients. The clinical correlate of fibrocystic disease is reflected by breast and axillary pain or tenderness in response to development of fibrocystic plaques, nodularity, macrocysts, and fibrocystic lumps. The disease progresses with advancing premenopausal age and is most pronounced in women during their 40s. Fibrocystic changes regress during the postmenopausal period.
The changes in fibrocystic breast disease are characterised by the appearance of fibrous tissue and a lumpy, cobblestone texture in the breasts. These lumps are smooth with defined edges, and are usually free-moving in regard to adjacent structures. The bumps can sometimes be obscured by irregularities in the breast that are associated with the condition. The lumps are most often found in the upper, outer sections of the breast (nearest to the armpit). Women with fibrocystic changes may experience a persistent or intermittent breast aching or breast tenderness related to periodic swelling. Breasts and nipples may be tender or itchy. Symptoms follow a periodic trend tied closely to the menstrual cycle. Symptoms tend to peak immediately before each period and decrease afterwards. At peak, breasts may feel full and swollen. No complications related to breastfeeding have been found.
Medical treatment of fibrocystic disease is accomplished: by suppression of ovarian estrogen secretion with a low-estrogen oral contraceptive, whereby the action of estrogen on breast tissues is opposed by the oral contraceptive's progestin component (19-nortestosterone derivatives), or by cyclic administration of a progestogen (progesterone, medroxyprogesterone acetate) that modulates the mammary effects of estrogen. These treatment modalities are equally as effective as or superior to danazol therapy, which entails side effects in the majority of patients. Adjuvant therapy of fibrocystic breast disease with vitamin E is of value in patients with borderline or abnormal lipid profiles (low plasma levels of high-density lipoprotein and high plasma levels of low-density lipoprotein). The estimated figures for the prevalence of fibrocystic breast changes in women over lifetime vary widely in the literature, with estimates ranging from about 30 to 60 % over about 50 to 60 % to about 60 to 75% of all women. The condition is most common among women between 30 and 50 years of age.