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The Voice of People With Breast Cancer


Breast Cancer Basics

High-Risk Conditions

Atypical Hyperplasia

Normally, there are 1 or 2 cell layers lining the ducts and lobules of your breast and these cells look similar under a microscope. In a condition called hyperplasia, these cells begin to grow, and the layers increase past the normal 1 or 2. Hyperplasia is a non-cancerous condition and can be usual or atypical. In usual hyperplasia, the cells become overgrown but still look close to normal. In atypical hyperplasia, the cells appear more distorted and abnormal. Atypical hyperplasia is a less common than usual hyperplasia and occurs in about 10% of all biopsies with benign (non-cancerous) findings. Atypical hyperplasia has many of the features of cancer, it does not have enough to be considered breast cancer. However, having atypical hyperplasia increases an individual's chances of being diagnosed with breast cancer: the risk is approximately 4 to 5 times higher than the risk for those without breast abnormalities. For this reason, it is considered to be a pre-malignant condition for breast cancer.

The risk factors of developing atypical hyperplasia are similar to the risk factors of developing breast cancer. This includes:

  • Age
  • Genetics and family history
  • Alcohol use
  • Breast density
  • Prior exposure to radiation
  • Lifestyle factors
  • Exposure to estrogen
  • Exposure to carcinogens

There are two types of atypical hyperplasia – atypical ductal hyperplasia (ADH) which is found in the ducts and atypical lobular hyperplasia (ALH) which is found in the lobules. ADH shares some of the features of ductal carcinoma in-situ (DCIS), a pre-cancer found in the breast ducts. ALH shares some of the features of lobular carcinoma in-situ (LCIS), an overgrowth of cells in the lobules that is also not considered cancer but a condition that increases an individual's risk of later developing breast cancer. E-cadherin is a type of protein associated with ADH. After being diagnosed with atypical hyperplasia, an E-cadherin test may be performed to determine whether you have ADH or ALH.

Both ADH and ALH occur at similar rates and individual diagnosed with either type have similar risks of later developing breast cancer. Research shows that the younger a woman is when she is diagnosed with either type of atypical hyperplasia, the higher her likelihood of being diagnosed with breast cancer later in life. 5 years after being diagnosed with atypical hyperplasia, 7% of women will be diagnosed with breast cancer; 10 years after an atypical hyperplasia diagnosis, 13% of women will be diagnosed with breast cancer; and 25 years after an atypical hyperplasia diagnosis, 30% of women with develop breast cancer.

Diagnosing Atypical Hyperplasia
There are no notable signs or symptoms of atypical hyperplasia; there may be breast pain, but this is very rare. It also cannot be detected through a breast exam or breast imaging. While atypical hyperplasia may appear on a mammogram or ultrasound as clusters of microcalcifications, the only way to diagnosis it is by a breast biopsy. This biopsy is usually done as follow-up testing of a suspicion mammogram or ultrasound result.

Treating and Managing Atypical Hyperplasia
After atypical hyperplasia is found, more tissue may be removed to ensure that there is nothing else there. If you’ve been diagnosed with atypical hyperplasia, you might consider getting a second opinion of your tissue samples to rule out early forms of breast cancer. There are a few options to treat atypical hyperplasia. Not all options will be available to you or will be ideal for you, as the options will depend on factors such as where you live or if you are considered high-risk due to other factors.

Close monitoring: Individuals diagnosed with atypical hyperplasia are usually advised to take a “wait and see” approach. In this case, increased screening mammograms may be encouraged and helpful in tracking any changes in breast tissue, ducts, and lobules. Additional breast screening methods might also be ideal.

Chemoprevention and aromatase inhibitors: Estrogen is a natural hormone in the body that has been found to increase the risk of developing breast cancer and making breast tumors grow. Certain drugs that the reduce risk of developing breast cancer by blocking the effects of estrogen may be suggested for individuals diagnosed with atypical hyperplasia. Tamoxifen is used for women not yet in menopause. For women in menopause or who have gone through menopause, exemestane, anastrozole or raloxifene, may be used. Aromatase inhibitors, which stop the enzyme aromatase from changing other hormones into estrogen, may also be used by post-menopausal women to reduce their risk of developing breast cancer following a diagnosis of atypical hyperplasia. Drugs such as these can reduce the risk of women with atypical hyperplasia going on to develop breast cancer by approximately 86%. It is important to note that these drugs only reduce the risk of getting ER-positive breast cancer, not ER-negative breast cancer. If you take any medicines with estrogen in them, such as birth control, your healthcare team may also suggest that you stop taking them.

Surgery: It’s important to weight the risks and benefits of having surgery to treat atypical hyperplasia since being diagnosed with it does not always mean that you will also be diagnosed with breast cancer. Surgery may be most suitable if you are at high-risk of developing breast cancer due to other factors, other than having atypical hyperplasia. Whether you are high-risk or not, speak to your healthcare team regarding which surgical option would be most ideal for you. Surgical options for treating atypical hyperplasia include:

  • Ultrasound-guided, vacuum-assisted excision – A fairly non-invasive method that removes the abnormal areas of the breast tissue. This is a common approach to treating atypical hyperplasia.
  • Lumpectomy – Involves removing the abnormal areas of the breast tissue along with parts of the surrounding tissue.
  • Prophylactic mastectomy – The removal of the entire breast tissue in one or both breasts. This option may be considered more ideal for individuals with atypical hyperplasia scattered in various areas of their breast tissue or those who have other high-risk factors for developing breast cancer.

An Overview Atypical Ductal Hyperplasia of the Breast from Very Well Health
Hyperplasia and Other Benign Breast Conditions from Susan G. Komen
Atypical Hyperplasia from Cleveland Clinic
Atypical Hyperplasia from Memorial Sloan Kettering Cancer Center
Learning About Atypical Hyperplasia of the Breast from Alberta Health Services
Hyperplasia and atypical hyperplasia from Breast Cancer Now
Atypical Hyperplasia of the Breast — Risk Assessment and Management Options from The New England Journal of Medicine
Hyperplasia of the Breast from American Cancer Society
Understanding Atypical Ductal Hyperplasia (ADH) from Healthline
Lobular Carcinoma in Situ (LCIS) and Atypical Lobular Hyperplasia from



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