Atypical Hyperplasia

This information explains what atypical hyperplasia is, what it means for your risk of getting breast cancer, and what screening and prevention strategies may be right for you.

About Atypical Hyperplasia

Hyperplasia is a condition in which there are more cells than usual in your breast. These cells start growing in your lobules (small round sacs that produce breastmilk) or in your ducts, (which carry the milk from your lobules to your nipples).

Usual hyperplasia is when the extra cells look like normal breast cells. In atypical hyperplasia, the extra cells look different from normal breast cells. Atypical means not typical or usual.

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Types of Atypical Hyperplasia

There are 2 main types of atypical hyperplasia: atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH).

Atypical Ductal Hyperplasia (ADH)

In ADH the new cells that grow look like the cells that grow in your breast ducts. While ADH is not yet a pre-cancer, it’s linked to an increased risk of getting breast cancer later on.

If ADH is found after a needle biopsy, you may need surgery to be sure that you don’t also have breast cancer. If you don’t have cancer, your doctor will talk with you about the screening guidelines that you should follow and ways you can lower your risk of developing breast cancer in the future.

 

Atypical Lobular Hyperplasia (ALH)

In ALH the new cells that grow look like the cells that grow in your breast lobules. ALH is linked to an increased risk of getting breast cancer.

When ALH is found after a needle biopsy, additional surgery is not always necessary. You and your doctor will decide whether surgery is right for you.

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Breast Cancer Screening

Women with either type of atypical hyperplasia should have regular breast exams and breast imaging tests. You and your doctor will decide what type of breast imaging is best for you, based on your personal history. At Memorial Sloan Kettering (MSK), we recommend a physical exam with a breast specialist and breast imaging every year.

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How to Lower Your Risk for Invasive Breast Cancer

Taking medications

Taking certain medications can help lower your risk of getting cancer. For breast cancer, you would take a pill once a day for 5 years. Studies have shown that these medications may lower your risk of breast cancer by more than 50%. Talk with your healthcare provider about the risks and benefits of these options so you can choose the one that is best for you.

Tamoxifen and raloxifene

Tamoxifen (Nolvadex®, Soltamox®) and raloxifene (Evista®) are medications that lower your risk of breast cancer by blocking the effects of estrogen. Estrogen is a hormone that supports the growth of many breast tumors. These medications only reduce your risk of estrogen receptor-positive breast cancer, which is the most common type. They will not reduce your risk of estrogen receptor-negative cancers.

You can take raloxifene only if you have already gone through menopause. You can take tamoxifen before or after menopause.

 

Aromatase inhibitors

Aromatase inhibitors are medications that stop an enzyme called aromatase from changing other hormones into estrogen. These medications are part of the standard treatment for breast cancer in women who have gone through menopause. One of these medications, exemestane (Aromasin®), has also been shown to lower the risk of breast cancer in women with atypical hyperplasia.

Prophylactic mastectomy

Bilateral prophylactic (PRO-fih-LAK-tik) mastectomy is the surgical removal of both breasts to try to prevent breast cancer. This surgery is rarely used to lower the risk of breast cancer in women with ADH or ALH.

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