An Overview Atypical Ductal Hyperplasia of the Breast

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Atypical ductal hyperplasia (ADH) is when a breast has more than the normal two layers of cells in the milk ducts and those additional cells are abnormal in size, shape, appearance, and growth pattern. It is not breast cancer but is considered a precancerous condition. Atypical ductal hyperplasia is diagnosed with a biopsy; it cannot be detected via a breast exam or imaging. If found, atypical ductal hyperplasia will require close monitoring.

ADH is similar to atypical lobular hyperplasia (ALH). However, ALH involves epithelial cells lining the lobules of the breast rather than the ducts.

Also Known As

Atypical ductal hyperplasia may also be called mammary atypical ductal hyperplasia, epithelial atypical hyperplasia, intraductal hyperplasia with atypia, or proliferative breast cancer.


Atypical ductal hyperplasia usually doesn't cause any notable symptoms. It is usually a subsequent finding of a biopsy done to evaluate a benign breast lump or area of thickening in the breast. Atypical ductal hyperplasia may cause breast pain, though this is rare.

Since ADL can go undetected until testing for a potential breast cancer diagnosis is done, it's important that you are aware of the signs and symptoms of breast cancer and see your doctor if you notice any changes in your breast that concern you.


A specific cause for atypical ductal hyperplasia is unknown. Normal cells overproduce. And as that continues, they begin to become irregular. If the condition is not properly managed, it will continue to progress and eventually become breast cancer. It may also affect nearby tissues. 

The risk factors for ADH are similar to those for all types of breast cancer, including:

  • Getting older: The risk for breast cancer and benign breast conditions increases with age; most breast cancers are diagnosed after age 50.
  • Genetic mutations: Inherited mutation of certain genes, such as BRCA1 and BRCA2
  • Reproductive health history: This includes early menstruation (before age 12) and starting menopause after age 55. Having a pregnancy after age 30, not breastfeeding, and never having a full-term pregnancy are also risk factors.
  • Have dense breast tissue: Dense breasts have more connective tissue than fatty tissue, which allows cancerous cells room to grow.
  • Family history: A woman’s risk is higher if she has a first-degree relative (parent, sibling, child) who has had breast cancer, or multiple family members (on both parents’ sides) who have had breast cancer.
  • Previous radiation treatments: A woman who has had previous radiation therapy to her chest or breasts before age 30 has a higher risk of getting breast cancer later one.
  • Activity level and/or weight: Not being active and/or being overweight after menopause can increase your risk.
  • Taking hormones: Birth control pills and hormone replacement therapy have been shown to raise risk.
  • Alcohol consumption: Overconsumption of alcohol may play a role.
  • Carcinogen exposure: Exposure to substances that cause cancer, including via smoking, also increases risk for breast cancer and benign breast conditions. 


Again, a breast biopsy is the only definitive test for diagnosing atypical ductal hyperplasia. A tissue sample may be obtained by either a core needle biopsy (needle localization biopsy during an ultrasound) or by an open surgical breast biopsy.

With ADH, the pattern of cell growth is abnormal and may have some features of ductal carcinoma in-situ (DCIS), which is pre-cancer in the ducts of the breast. When a biopsy finds atypical ductal hyperplasia, more tissue will be surgically removed and tested to make sure there is nothing else more serious in breast tissue.

Your doctor may recommend a breast biopsy if you present with certain signs or symptoms of breast cancer (particularly if you have risk factors for the disease), or may do so only after other, less invasive tests are done.

Though the following cannot confirm a diagnosis of atypical ductal hyperplasia, they may yield results that strengthen the possibility of one:

  • Mammography: ADH often appears as a pattern of calcifications on a mammogram.
  • Ultrasound: An ultrasound uses sound waves to assess the appearance of a lump or thickening in the breast and may also reveal calcifications.
  • Ductal lavage: Breast cells are withdrawn through the nipple using a suction technique. Under the microscope, some of these cells may appear atypical.

Though a ductal lavage may find cells that are atypical, a breast biopsy does this and allows your physician to determine the location of those cells.

Follow-Up and Treatment

Once you've been diagnosed with ADH, you'll be asked to make a choice about what to do next. You have several options, all of which are worth discussing in relation to your health and history with your physician.

Watching and Waiting

Physicians will often advise women to take a "wait and see" approach to ADH. Many people opt for extra screening mammograms alone to keep track of any changes.

The rationale behind this is that surgery to remove the atypical tissue carries risks that may be unnecessary for you, as at least half of women with ADH will not go on to develop breast cancer.

One 2014 report in the Journal of Breast Cancer suggested the women with ADH who were most likely to go on to develop breast cancer were less than 50 years old, had microcalcifications on their mammogram, a mass smaller than 15 millimeters, and a palpable (able to be found with touch) lump.


Your doctor may suggest medications that prevent breast cancer, including selective estrogen receptor modulators (SERMs) that block estrogen from acting on certain cells. 


Surgery may be a better choice if you are at high risk of developing breast cancer—for example, you are younger than age 50 with larger tumors or tumors that can be felt on exam. That said, it is also an option if you don't have such risk factors but are very concerned about your diagnosis of atypical ductal hyperplasia.

In either cases, but particularly if you are not considered high-risk, speak with your doctor about the pros and cons of your surgical options:

  • Ultrasound-guided, vacuum-assisted excision: This is a relatively non-invasive method of removing the atypical area of tissue. However, it may not be appropriate for everyone.
  • Lumpectomy: Lumpectomy involves removing the tissue containing the area of abnormal cells plus a margin of surrounding tissue to help prevent recurrence.
  • Mastectomy: Some women have areas of ADH that are widely scattered throughout their breast(s). When this occurs, a woman may opt to have a mastectomy to remove all potentially abnormal breast tissue.

A Word From Verywell

What you choose to do about your atypical ductal hyperplasia is very personal. Regardless of what you choose to do, your diagnosis can serve as an impetus to work harder at lowering your modifiable risk factors for breast cancer and improving your health in general. For example, consider adopting an anti-cancer diet, regularly exercise, lowering stress levels, performing breast self-exams, and committing to routine breast screenings.

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