Hyperplasia of the Breast (Ductal or Lobular)

Hyperplasia is also known as epithelial hyperplasia or proliferative breast disease. It’s an overgrowth of the cells that line the ducts or the milk glands (lobules). Hyperplasia may be called either ductal hyperplasia (also called duct epithelial hyperplasia) or lobular hyperplasia based on how the cells look under a microscope.

Ductal and lobular hyperplasia occur at about the same rate, and have much the same effect on breast cancer risk.

Hyperplasia is often described as usual or atypical based on the pattern of the cells.

  • In usual hyperplasia, the pattern of cells is very close to normal.
  • The cells are more distorted in atypical hyperplasia (or hyperplasia with atypia).1 This can be either atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH).


Hyperplasia doesn’t usually cause a lump that can be felt, but it can cause changes that can be seen on a mammogram. It’s diagnosed by doing a biopsy . (A hollow needle may be used to remove a small piece of tissue that’s checked under a microscope. Or, surgery may be done to take out the breast tissue with hyperplasia.)


Most types of hyperplasia do not need to be treated. But if atypical hyperplasia (ADH or ALH) is found on a needle biopsy, more breast tissue around it might be removed to be sure that there is nothing more serious nearby.1

Some types of hyperplasia are linked to a higher risk of breast cancer (see below). Most women with hyperplasia, especially atypical hyperplasia, need to see a health care provider more often. They may need regular breast exams, mammograms, and breast MRIs .

Some women with atypical hyperplasia choose to take medicine to help lower their risk of breast cancer. More on this can be found in Deciding Whether to Use Medicine to Reduce Breast Cancer Risk

Most women with atypical hyperplasia will not develop breast cancer.1 It’s important to talk with a health care provider about your risk and what, if any, treatment is best for you.

How does hyperplasia affect your risk for breast cancer?

Different types of hyperplasia can affect breast cancer risk:

  • Mild hyperplasia of the usual type: This does not increase the risk for breast cancer.
  • Moderate or florid hyperplasia of the usual type (without atypia), also known as usual hyperplasia: The risk of breast cancer is about 1½ to 2 times that of a woman with no breast abnormalities.
  • Atypical hyperplasia (either ADH or ALH): The risk of breast cancer is about 4 to 5 times higher than that of a woman with no breast abnormalities.2, 3 More details about pathology reports showing atypical hyperplasia can be found in Understanding Your Pathology Report: Atypical Hyperplasia.

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Guray M, Sahin AA. Benign breast diseases: Classification, diagnosis, and management. Oncologist. 2006;11:435-449.

1 Hartmann LC, Degnim AC, Santen RJ, Dupont WD, Ghosh K. Atypical hyperplasia of the breast — Risk assessment and management options. N Engl J Med. 2015;372:78-89.

Hartmann LC, Sellers TA, Frost MH, et al. Benign breast disease and the risk of breast cancer. N Engl J Med. 2005;353:229-237.

McEvoy MP, Coopey SB, Mazzola E, et al. Breast cancer risk and follow-up recommendations for young women diagnosed with atypical hyperplasia and lobular carcinoma in situ (LCIS). Ann Surg Oncol. 2015;22:3346-3349.

National Cancer Institute. Understanding Breast Changes: A Health Guide for Women. April 23, 2015. Accessed at www.cancer.gov/types/breast/understanding-breast-changes on June 9, 2016.

3 Obeng-Gyasi S, Ong C, Hwang ES. Contemporary management of ductal carcinoma in situ and lobular carcinoma in situ. Chin Clin Oncol. 2016 May 11. [Epub ahead of print]

2 Schnitt SJ, Collins LC. Pathology of benign breast disorders. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 4th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2010:69-85.


Last Medical Review: March 16, 2015 Last Revised: April 21, 2016

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