Sclerosing adenosis of the breast

by Jason Wasserman MD PhD FRCPC
November 6, 2022

What is sclerosing adenosis?

Sclerosing adenosis is a non-cancerous growth made up of small glands in the breast. The glands are surrounded by a type of connective tissue that resembles a scar. When large enough, this type of growth can be seen in imaging studies such as mammography, and a biopsy may be performed to rule out cancer.

What are the symptoms of sclerosing adenosis?

Sclerosing adenosis alone rarely causes any symptoms and usually cannot be felt as a discrete lump in the breast. This condition is often only detected after imaging such as mammography.

What causes sclerosing adenosis?

At present we do not know what causes sclerosing adenosis.

Is sclerosing adenosis considered a precancerous condition?

No. Sclerosing adenosis is not considered a precancerous condition.

Is sclerosing adenosis associated with an increased risk of developing breast cancer?

A person with sclerosing adenosis has a 1.5 to 2-fold increased lifetime risk of developing breast cancer compared to a person without this condition.

How is the diagnosis of sclerosing adenosis made?

The diagnosis of sclerosing adenosis is made after tissue is examined under a microscope by a pathologist. The tissue often comes from a biopsy performed to investigate an abnormal area in the breast. However, sclerosing adenosis is also commonly an incidental (accidental) finding in breast tissue removed for the purpose of treating another condition such as breast cancer.

What does sclerosing adenosis look like under a microscope?

When examined under a microscope, sclerosing adenosis is made up of round structures called glands arranged in groups called lobules. The glands are often surrounded by a dense connective tissue called collagen that resembles a scar. Small deposits of calcium called microcalcifications are commonly seen both within the glands and the connective tissue.

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