What Is Atypical Lobular Hyperplasia?

Atypical lobular hyperplasia (ALH) is the abnormal growth of cells in the milk-producing glands of the breast (known as lobules). ALH specifically affects epithelial cells lining the walls of lobules.

ALH is a precancerous condition that could lead to the earliest stage of breast cancer, known as ductal carcinoma in situ (DCIS). Because the risk of cancer is increased if you have ALH, you would need to undergo routine breast cancer screening. Others at high risk of breast cancer may be advised to undergo surgery.

This article explains the symptoms and causes of atypical lobular hyperplasia, including how it is diagnosed and treated. It also describes the odds of getting breast cancer if diagnosed with ALH.

Symptoms of Atypical Lobular Hyperplasia

Atypical lobular hyperplasia doesn't usually cause any symptoms, although it can cause non-specific breast pain in some people. Most people are unaware they have ALH until they get the results of a routine mammogram.

This is because ALH doesn't usually cause a lump. If it does, it is usually very small and unlikely to be noticed during a breast self-exam.

Causes and Risk Factors of ALH

The exact cause of atypical lobular hyperplasia is unknown. Scientists believe it is the result of lifetime exposure to the female sex hormone estrogen. It usually affects females in their 40s and can also affect men, albeit very rarely.

Risk factors of ALH include:

• Starting menstrual periods in early adolescence
• Going through menopause at an older age
• Using estrogen replacement therapy after menopause
• Having a family history of breast cancer or ovarian cancer

ALH is similar to atypical ductal hyperplasia (ADH) which also causes the proliferation of abnormal cells in the ducts leading from the lobules.

How Serious Is ALH and the Risk of Breast Cancer?

Atypical lobular hyperplasia is a high-risk, precancerous lesion that can evolve into ductal carcinoma in situ (DCIS).

DCIS is a condition that affects the epithelial cells that line the walls of a breast lobule. Carcinomas are cancers that specifically affect epithelial cells.

Over time, DCIS can turn into invasive ductal carcinoma (IDC), the most common type of breast cancer. Depending on the grade of the tumor, it can take anywhere from three to nine years for DCIS to evolve into IDC.

Research suggests that the risk of developing breast cancer is as high as 20% if you have been diagnosed with ALH. That is significantly higher than the overall risk of breast cancer among females in the United States, which runs around 13%.

How Atypical Lobular Hyperplasia Is Diagnosed

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

• Mammogram: On a mammogram, ALH may appear as a cluster of white spots due to microcalcification (tiny calcium deposits in tissues)
• Breast ultrasound: This non-invasive imaging tool may be able to detect larger consolidated lesions or lumps
• Breast biopsy: This is the definitive method of diagnosis of ALH. Under the microscope, epithelial cells will look abnormal and be tightly packed and haphazardly arranged.

ALH is found in 5% to 20% of breast biopsies.

How Is Atypical Lobular Hyperplasia Treated?

Many cases of ALH do not require treatment and will instead be monitored regularly to check for any changes in breast tissues. This is called active surveillance.

Some people may be advised to undergo surgery, either in the form of a wide local excision (used to remove all the affected tissues along with a small margin of unaffected tissues) or a lumpectomy (if an actual lump is present).

Candidates for surgery include those at high risk of breast cancer who:

• Have a family history of breast or ovarian cancer
• Tests positive for a BRCA gene mutation
• Has multiple lesions

It is difficult to predict which cases of ALH will remain benign and which may turn cancerous, so surveillance is essential. This may include extra screening mammograms and/or breast magnetic resonance imaging (MRI) to identify any changes as early as possible.

Breast cancer fisk-reduction strategies are also advised, including:

• Keeping a healthy weight
• Quitting cigarettes
• Staying physically active
• Avoiding alcohol
• Eating a low-fat diet

You should also ask your healthcare provider if hormonal birth control or estrogen replacement therapy is right for you given that they can increase the risk of certain cancers.

For some, medication such as tamoxifen and raloxifene may reduce the risk of breast cancer by up to 70%.

Summary

ALH is a type of precancer in which abnormal cells develop in the milk-producing glands of the breast. ALH can lead to an early-stage cancer called ductal carcinoma in situ (DCIS) in up to one of every five people with ALH.

ALH often does not require treatment but will instead be regularly monitored with a screening mammogram and/or a breast MRI. Some people at high risk of breast cancer may have the ALH lesions removed just to be safe.