Atypical Lobular Hyperplasia of the Breast

Mammogram results. : B. BOISSONNET /BSIP, Getty Images

Description of Atypical Lobular Hyperplasia:

Atypical lobular hyperplasia (ALH) is not breast cancer, but is considered a precancerous condition. Atypical lobular hyperplasia occurs in the epithelial cells lining the milk lobes, producing more cells than would normally grow there. Some of these cells are irregular in shape and size, thus they are called atypical. Usually, a lobe is lined with one even layer of uniformly shaped cells, but in lobular hyperplasia there may be several layers of cells.

This is similar to atypical ductal hyperplasia.

Increased Risk for Breast Cancer:

A diagnosis of atypical lobular hyperplasia means that your lifetime risk for developing breast cancer is 4 to 5 times the average risk. Atypical lobular cells are abnormal and have the potential for developing into lobular carcinoma in situ (LCIS), a type of noninvasive breast cancer. You will need to be vigilant about your breast health, and may possibly have a breast MRI along with your annual screening mammogram. Women between the ages of 45 to 55 with atypical hyperplasia have the highest future risk of developing breast cancer.

Also Known As:

Lobular hyperplasia with atypia, mammary atypical lobular hyperplasia, epithelial atypical hyperplasia or proliferative breast disease

Signs and Symptoms:

Atypical lobular hyperplasia doesn't cause any notable symptoms. It is usually found on a routine screening mammogram.

In a few cases, atypical lobular hyperplasia may cause breast pain. When hyperplasia shows up on a mammogram or ultrasound, a tissue sample can be taken to get a clear diagnosis.

Tests Used to Diagnose ALH:

You may not need all of these diagnostic tests, but some imaging and a tissue sample will be needed to get a clear diagnosis.

Follow-up After Diagnosis:

It is difficult to predict which cases of atypical lobular hyperplasia will remain benign and which may become malignant, and doctors can disagree on what your options are after diagnosis. Many patients just need extra screening mammograms to keep track of any changes. Some patients may choose a type of surgery to remove the suspicious tissue. If you have a family history of breast or ovarian cancer, or if you have a BRCA genetic mutation, you'll need to balance that in with your treatment decisions.

Treatment Options for Atypical Lobular Hyperplasia:

Women with ALH should be advised to stop taking oral contraceptives, avoid hormone replacement therapy, and make appropriate lifestyle and dietary changes that may decrease their risk of breast cancer (i.e. A diet rich in fruits and vegetables, fish, and olive oil and regular exercise).

They should be encouraged to see a specialist that would calculate their risk of developing invasive breast cancer using the Gail model. The benefits and risks should be discussed accordingly and, primary prevention using tamoxifen or raloxifene, may be recommended for some women.

If ​ ALH is found by a core needle biopsy a surgical excision should be performed to avoid underestimation of the diagnosis.

Living With a Diagnosis of Atypical Lobular Hyperplasia:

About one out of every 25 women will be diagnosed with atypical hyperplasia – either in their milk ducts or breast lobes. About 20% percent of those women may develop lobular carcinoma in situ or invasive lobular carcinoma within 15 years after their diagnosis. 

A Word from Verywell

If you are diagnosed with atypical lobular hyperplasia, do what you can do to reduce your risk of developing a breast cancer. See a nutritionist and develop a healthy eating plan. Watch your weight, keep alcohol consumption to a minimum and don't smoke. Get regular checkups

Edited by​: Jean Campbell, MS


Non-Cancerous Breast Conditions: Hyperplasia.American Cancer Society. Last Revised: 09/16/2010.

Tests For Risk: Precancer Found on Biopsy. Pp180-183. Dr. Susan Love's Breast Book.Susan M. Love, M.D. Fifth Edition, 2010.

The diagnosis and management of pre-invasive breast disease: Pathology of atypical lobular hyperplasia and lobular carcinoma in situ. Peter T Simpson, Theodora Gale, Laura G Fulford, Jorge S Reis-Filho,and Sunil R Lakhani. Breast Cancer Res. 2003; 5(5): 258-262.

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