An Overview of Atypical Lobular Hyperplasia of the Breast

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Atypical lobular hyperplasia (ALH) is an overgrowth of unusual-looking cells in the lobes of the breast, specifically in the epithelial cells lining the lobes. This condition is not breast cancer, but it is considered a precancerous condition that could lead to ductal carcinoma in situ (DCIS), which is considered the earliest stage of breast cancer. ALH is found in 5% to 20% of breast biopsies. Because your risk of breast cancer is higher than average if you have ALH, you will need close monitoring.

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ALH is similar to atypical ductal hyperplasia (ADH), which causes more cells to develop in the lining of the breast ducts (milk producing glands).

This article will review symptoms of atypical lobular hyperplasia, how it is diagnosed, and how it is treated.

Also Known As

ALH is also known as lobular hyperplasia with atypia, mammary atypical lobular hyperplasia, epithelial atypical hyperplasia, and proliferative breast disease.


Atypical lobular hyperplasia typically doesn't cause any notable symptoms, though it may cause breast pain in some cases. Most people are unaware of the condition until they get the results of routine breast imaging.

That said, since atypical lobular hyperplasia can lead to breast cancer, make sure you bring any abnormalities you notice during a breast self-exam to the attention of your healthcare provider. These may include: 


An exact cause of atypical lobular hyperplasia is unknown. Healthcare providers believe it is a natural part of breast changes for some women as they get older and may be related to a lifetime of exposure to estrogen. It often affects women over 35, but it can affect women regardless of age. It may also affect men but is very rare.

Risk factors of ALH are similar to those for other benign breast conditions, including:

  • Postmenopausal hormone use
  • Family history of breast cancer and benign breast conditions
  • Certain lifestyle factors, including over-consumption of alcohol, smoking, being overweight, and having an unhealthy diet


Imaging and a tissue biopsy are needed to confirm an atypical lobular hyperplasia diagnosis.

  • Mammogram: ALH may appear as a cluster of microcalcifications on a mammogram.
  • Ultrasound: A breast ultrasound uses sound waves to reveal groups of microcalcifications.
  • Breast biopsy: A breast biopsy is the most definitive method for diagnosis of ALH. It allows a pathologist to determine the location and nature of your cells. The pattern of growth seen in atypical lobular hyperplasia is abnormal and may contain cells that are characteristic of lobular carcinoma in situ (LCIS)—an overgrowth of cells in the lobules.

In some cases—for example, when someone has a family history of breast or ovarian cancer, or is positive for a BRCA gene mutation—an excisional biopsy may be done to remove the suspicious tissue.


Some people with atypical lobular hyperplasia may benefit from undergoing surgery to remove abnormal cells and make sure no in-situ and invasive cancer cells are also present in the area. However, most cases of ALH do not require treatment.

It is difficult to predict which cases of atypical lobular hyperplasia will remain benign and which may become malignant, so surveillance is essential.

This will include extra screening mammograms and/or breast magnetic resonance imaging (MRIs) to identify any breast changes as early as possible. A commitment to risk-reduction strategies is also recommended.

While having atypical lobular hyperplasia increases one's lifetime risk of breast cancer by up to 2%, prevention methods have been found to reduce that risk by up to 70% in women with ALH or other high-risk breast conditions.

Your healthcare provider will advise you to avoid oral contraceptives and hormone replacement therapy (HRT), as both further increase your risk of developing breast cancer. Adopting certain lifestyle strategies, such as getting regular exercise and eating a low-fat diet, can also help prevent the disease. For some, medication such as tamoxifen and raloxifene may reduce breast cancer risk.


Not to be confused with breast cancer, ALH is an overgrowth of unusual-looking cells in the lobes of the breast, specifically in the epithelial cells lining the lobes. It is however, a precancerous condition that should be monitored by a breast specialist. Extra mammograms may be in order and some people benefit from having the cells removed in a surgical procedure.

A Word From Verywell

Learning of any abnormality in your breast is concerning, but remember that atypical lobular hyperplasia is not cancer. It does, however, mean that prevention strategies are perhaps more important to you now than ever. Take control of your condition by doing all that you can to affect modifiable risk factors. Be sure you are clear about your recommended screening schedule, get regular checkups, and consider seeking the advice of health professionals, such as a nutritionist, to help you in your efforts.

Frequently Asked Questions

  • What causes atypical lobular hyperplasia?

    There's no known precise cause of atypical lobular hyperplasia. Healthcare providers believe it is a natural part of breast changes for some women as they get older.

  • Can atypical lobular hyperplasia become cancer?

    Yes. This condition is a precursor to the earliest form of breast cancer, called ductal carcinoma in situ (DCIS).

  • Is atypical lobular hyperplasia genetic?

    It can be. The risk is doubled with family history.

  • How common is atypical lobular hyperplasia?

    This condition is pretty common, especially among women age 35 and older. ALH is found in 5% to 20% of breast biopsies.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Myers DJ, Walls AL. Atypical breast Hyperplasia. In: StatPearls. StatPearls Publishing; 2021.

  2. Lobular neoplasia (atypical lobular hyperplasia and lobular carcinoma in situ).

  3. American Cancer Society.Tamoxifen and raloxifene for lowering breast cancer risk.

  4. Kader T, Hill P, Rakha EA, et al. Atypical ductal hyperplasia: update on diagnosis, management, and molecular landscape. Breast Cancer Res. 2018;20(1):39. doi:10.1186/s13058-018-0967-1

Additional Reading
Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
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