Overview

Breast cysts are fluid-filled sacs inside the breast, which are usually not cancerous (benign). You can have one or many breast cysts and they can happen in one or both breasts. They're often described as round or oval lumps with distinct edges. A breast cyst usually feels like a grape or a water-filled balloon, but sometimes a breast cyst feels firm.

Breast cysts don't require treatment unless a cyst is large and painful or uncomfortable. In that case, draining the fluid from a breast cyst can ease symptoms.

Breast cysts are common in women before menopause, between ages 35 and 50. But they can be found in women of any age. They can also occur in postmenopausal women taking hormone therapy.

Symptoms

Breast cysts may be found in one or both breasts. Signs and symptoms of a breast cyst include:

  • A smooth, easily movable round or oval lump with distinct edges (which typically, though not always, indicates it's benign)
  • Nipple discharge that may be clear, yellow, straw colored or dark brown
  • Breast pain or tenderness in the area of the breast lump
  • Increase in breast lump size and breast tenderness just before your period
  • Decrease in breast lump size and resolution of other symptoms after your period

Having breast cysts doesn't increase your risk of breast cancer. But having cysts may make it more difficult to find new breast lumps or other changes that might need evaluation by your doctor. Be familiar with how your breasts normally feel so that you'll know when something changes.

When to see a doctor

Normal breast tissue often feels lumpy or nodular. But if you feel any new breast lumps that persist after a menstrual period, or if an existing breast lump grows or changes, see your doctor right away.

Causes

Each of your breasts contains lobes of glandular tissue, arranged like petals of a daisy. The lobes are divided into smaller lobules that produce milk during pregnancy and breast-feeding. The supporting tissue that gives the breast its shape is made up of fatty tissue and fibrous connective tissue.  Breast cysts develop as a result of fluid accumulation inside the glands in the breasts.

Breast cysts may be defined by their size:

  • Microcysts are too small to feel, but may be seen during imaging tests, such as mammography or ultrasound.
  • Macrocysts are large enough to be felt and can grow to about 1 to 2 inches (2.5 to 5 centimeters) in diameter. Large breast cysts can put pressure on nearby breast tissue, causing breast pain or discomfort.

Experts don't know what causes breast cysts. They may develop as a result of hormonal changes from monthly menstruation. Some evidence suggests that excess estrogen in your body, which can stimulate the breast tissue, may contribute to breast cysts.

Oct. 08, 2015
References
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