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Learning About Atypical Hyperplasia of the Breast

Side view of breast, with close-up of ducts and lobes

What is it?

Atypical hyperplasia of the breast is an overgrowth of certain cells in the breast. These cells line the ducts and lobes of the breast. They aren't shaped like normal cells.

It isn't cancer. But having it may increase the risk of getting breast cancer.

There are two types. They are atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH).

What causes it?

The exact cause isn't known. Age, past health, and family health history play a part.

What are the symptoms?

Usually there are no symptoms of atypical hyperplasia. The changes in breast tissue are too small to be felt.

How is it diagnosed?

It's diagnosed with a biopsy of breast tissue. This is done after a mammogram finds changes in breast tissue that don't look normal.

A breast biopsy is a test to look at a small sample of tissue that has been removed from the breast. The sample is looked at under a microscope. If you have atypical hyperplasia, the doctor can see the abnormal cells in the sample tissue.

To take the sample, your doctor may use a needle or probe. Your doctor may need to make a small cut in the skin to remove all or part of the area found on the mammogram.

How is it treated?

Atypical hyperplasia may be treated by removing the abnormal cells. This often depends on which type of the disease you have. In some cases, the cells were all removed during the breast biopsy. But the doctor may need to make a small cut in the skin to take out more cells.

You will work with your doctor to manage your risk of breast cancer. The doctor will ask about your family history of cancer. You may have a breast exam every 6 months and a mammogram once a year. Your doctor may suggest that you have an MRI scan of the breast.

Your doctor may prescribe medicines to help prevent breast cancer. These may include tamoxifen. If you are past menopause, the medicines may also include raloxifene or exemestane.

Your doctor is likely to recommend that you do not take medicines with estrogen in them. These include birth control pills and hormone replacement therapy. They increase the risk of breast cancer.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Where can you learn more?

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