The cause is not completely understood, but the changes are believed to be associated with ovarian hormones since the condition usually subsides with menopause, and may vary in consistency during the menstrual cycle.

The incidence of it is estimated to be over 60% of all women. It is common in women between the ages of 30 and 50, and rare in postmenopausal women. The incidence is lower in women taking birth control pills. The risk factors may include family history and diet (such as excessive dietary fat, and caffeine intake), although these are controversial.

• A dense, irregular and bumpy "cobblestone" consistency in the breast tissue
• Usually more marked in the outer upper quadrants
• Breast discomfort that is persistent, or that occurs off and on (intermittent)
• Breast(s) feel full
• Dull, heavy pain and tenderness
• Premenstrual tenderness and swelling
• Breast discomfort improves after each menstrual period
• Nipple sensation changes, itching

Note: Symptoms may range from mild to severe. Symptoms typically peak just before each menstrual period, and improve immediately after the menstrual period.

Physical examination reveals the presence of mobile (non-anchored) breast "masses". These masses are usually rounded, with smooth borders, and either rubbery or slightly fluctuant (changeable in shape). Dense tissue may make the breast examination more difficult to interpret.

• Mammography may be difficult to interpret due to dense tissue.
• A biopsy of the breast may be necessary to rule out other disorders.
• Aspiration of the breast with a fine needle is often diagnostic and therapeutic for larger cysts.

Self care may include restricting dietary fat to approximately 25% of the total daily calorie intake, and eliminating caffeine intake.

Performing a breast self-examination monthly, and wearing a well-fitting bra to provide good breast support are important.

The effectiveness of Vitamin E, Vitamin B6, and herbal preparations, such as evening primrose oil are somewhat controversial. Discuss their use with your health care provider.

Oral contraceptives may be prescribed because they often decrease the symptoms. A synthetic androgen may be prescribed by a doctor in severe cases, when the potential benefit is thought to outweigh the potential adverse effects.

If dietary changes decrease the symptoms, and are maintained, the benefit most likely will persist. A combination of treatment and use of medications may be necessary to obtain relief for severe cases.

Because fibrocystic changes may make breast examination and mammography more difficult to interpret, early cancerous lesions may occasionally be overlooked.

Call your health care provider if you feel a new, unusual, or "dominant" lump during a breast self-examination.

Call for an appointment with your health care provider if you are a woman, aged 20 or older, who has never been taught, or does not currently know how to perform breast self-examination. Or call if you are a woman, aged 40 or older, who has not had a screening mammogram.

Reduction of dietary fat and caffeine if you have fibrocystic breast changes has been suggested, although recent studies have questioned the role of caffeine and fat in fibrocystic disease.