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Breast cancer

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Other benign breast conditions

The breast can be affected by other benign breast conditions.

Radial scars

Radial scars are star-shaped lesions (abnormal area of tissue) made up of gland and supportive tissue fibres in the breast. They are not really scars, but they look like scars when examined under a microscope. Radial scars may slightly increase the risk of breast cancer because they are made up of cells that multiply at a faster than normal rate (proliferative).

  • They are often found during mammography or when breast tissue that has been removed is examined under a microscope.
  • Most radial scars are very small (less than 10 mm) and cannot be felt in the breast.
    • Radial scars that are larger than 1 cm may be called complex sclerosing lesions.
  • Radial scars are often removed by surgery because they look like an invasive breast cancer on a mammogram.

Fat necrosis

Fat necrosis occurs when fatty tissue of the breast is damaged or injured and replaced by scar tissue. Fat necrosis does not increase a woman’s risk of breast cancer.

  • Fat necrosis is more common in women with very large breasts.
  • The most common causes of injury to the breast are surgery or radiation therapy.
    • Seat belt injury or blows to the chest may also cause fat necrosis.
  • It is usually found during mammography or ultrasound.
  • Biopsy may be done to confirm the diagnosis:
  • Most fat necrosis areas disappear without treatment.
  • Surgery may be offered if:
    • the biopsy did not confirm the diagnosis of fat necrosis
    • the area grows or begins to cause symptoms


Adenosis is a benign breast condition in which the lobules of the breast become enlarged due to the presence of more than the normal number of milk glands. Adenosis does not increase a woman’s risk of developing breast cancer.

When the enlarged lobules are surrounded by scar-like tissue, it is called sclerosing adenosis. Women with sclerosing adenosis of the breast have a slightly greater risk of developing breast cancer.

  • Adenosis is usually found during a mammogram.
    • In some cases, adenosis can be felt during a clinical breast exam if there is a group of enlarged lobules close together.
  • Core needle biopsy may be done to confirm the diagnosis and rule out the presence of cancer.
  • Adenosis is a benign condition and treatment is usually not necessary.
  • Women with sclerosing adenosis should speak to their doctor about early detection and screening for breast cancer.


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