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Breast cancer

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Breast cysts

Breast cysts are fluid-filled sacs in the breast tissue. They are the most common benign breast lumps in women between the ages of 35 and 50. Breast cysts do not increase the risk of breast cancer. Most breast cysts are benign and are rarely cancerous.

Risk factors

There are no known causes of breast cysts. It is thought that they are caused by the changes in hormoneshormonesA substance that regulates specific body functions, such as metabolism, growth and reproduction. that control a woman’s menstrual cycle.

Women who are taking hormone replacement therapy (HRT)hormone replacement therapy (HRT)Treatment that replaces female sex hormones ( estrogen, progesterone or both) when they are no longer produced by the ovaries. after menopause may also develop breast cysts.

Signs and symptoms

A woman can have one or many breast cysts. The signs and symptoms of a breast cyst may include:

  • lump(s) in the breast that feel smooth, soft and moveable
    • The edges of the cyst are very distinct from the surrounding breast tissue.
  • lump(s) that becomes larger, tender and painful before or during a woman’s period
    • The lump and pain may decrease after the period.

Very small breast cysts may not cause any signs and symptoms.


If the signs and symptoms of a breast cyst are present, or if the doctor suspects a breast cyst, tests will be done to make a diagnosis. Tests may include:


If the cyst is large, or does not go away on its own, treatment options for breast cysts may include:

  • watching the cyst over time for any changes
    • Many breast cysts disappear without treatment.
  • fine needle aspiration
  • surgery – may be an option for cysts that:
    • come back after fine needle aspiration
    • have blood in the fluid removed during fine needle aspiration
    • are large and cause pain


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