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Hyperplasia of the Breast
Hyperplasia happens when the cells that line the lobules (milk-producing glands) or ducts (small tubes) inside the breast grow and multiply more than usual. It is not cancer, but some types of hyperplasia are linked with a higher risk of developing breast cancer.
How is hyperplasia diagnosed?
Hyperplasia doesn’t usually cause a lump that can be felt, but it can sometimes cause changes that can be seen on a mammogram. It’s diagnosed by doing a breast biopsy. During the biopsy, a hollow needle or surgery is used to take out some of the abnormal breast tissue for testing.
Hyperplasia can be described as either usual or atypical. This is based on how the cells look under a microscope.
- In usual ductal hyperplasia (UDH), also called hyperplasia of the usual type or ductal hyperplasia without atypia, there is an extra growth of cells lining the ducts in the breast, but the cells look close to normal.
- In atypical hyperplasia (or hyperplasia with atypia), the extra cell growth looks much different than normal cells. This can be either atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH).
For more on atypical hyperplasia, see Understanding Your Pathology Report: Atypical Hyperplasia.
How does hyperplasia affect breast cancer risk?
Having hyperplasia can increase your risk of breast cancer. How much depends on what type it is.
- Usual ductal hyperplasia: The risk of breast cancer is about 1? to 2 times higher than that of a woman with no breast hyperplasia.
- Atypical hyperplasia (ADH or ALH): The risk of breast cancer is about 4 to 5 times higher than that of a woman with no breast hyperplasia.
Does hyperplasia need to be treated?
Usual ductal hyperplasia is a common finding on a breast biopsy and does not need to be treated.
If either ADH or ALH is found on a biopsy, surgery may be recommended to remove more breast tissue around it. This helps make sure that there is nothing more serious, such as cancer, nearby. This is more likely to be done for ADH than for ALH. Another option (especially for ALH) might be close follow up with physical exams and imaging tests, like mammograms.
If ADH or ALH is found after a surgical (excisional) biopsy, often no other treatment is needed. However, if there’s a concern that ADH might not have been removed completely, further surgery might be recommended.
Reducing breast cancer risk or finding it early
Both ADH and ALH are linked to a higher risk of breast cancer. Even though most women with ADH or ALH will not develop breast cancer, it's still important to talk with a health care provider about your risk and what you can do about it.
Options for women at higher risk of breast cancer from ADH or ALH may include:
- Getting breast exams more often, likely every 6 or 12 months along with a yearly mammogram. Additional imaging with breast MRIs may also be recommended, especially if you have other factors that raise your risk of breast cancer.
- Making lifestyle changes to lower breast cancer risk. To learn more, see Can I Lower My Risk of Breast Cancer?
- Taking medicine to help lower breast cancer risk. For more on this, see Deciding Whether to Use Medicine to Reduce Breast Cancer Risk.
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- References
Developed by the 黑料大湿Posts Cancer Society medical and editorial content team with medical review and contribution by the 黑料大湿Posts Society of Clinical Oncology (ASCO).
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Last Revised: May 26, 2026
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