Mammary Duct Ectasia


What is mammary duct ectasia?

Mammary duct ectasia is a noncancerous breast condition causing inflammation (swelling) and a thickening of the milk ducts. It is also known as duct ectasia or periductal mastitis.

Who is likely to have mammary duct ectasia?

Anyone can have mammary duct ectasia. The condition is more common among women who are approaching menopause. It can also occur after menopause.

Symptoms and Causes

What causes mammary duct ectasia?

Mammary duct ectasia results from inflammation (swelling). This inflammation causes a milk duct within the breast to widen and thicken. As inflammation worsens, milk ducts become blocked, and fluid builds up behind the blockage.

While the exact cause of this inflammation is unknown, researchers think that bacterial infection of the milk ducts make it more likely for a woman to develop mammary duct ectasia.

What are the symptoms of mammary duct ectasia?

For many women, periductal mastitis causes no symptoms. However, some women experience symptoms that can include:

  • Breast tenderness
  • Redness
  • Inverted nipple (nipple turning inward)
  • Thick nipple discharge that may be green or black

In a small number of women, mammary duct ectasia causes lumps to form in the breast. Lumps develop as a result of scar tissue that forms around inflamed milk ducts. The lump may be confused with breast cancer, but it is not cancer.

Diagnosis and Tests

How is mammary duct ectasia diagnosed?

Your doctor diagnoses mammary duct ectasia by removing a small sample of breast tissue from the affected breast. This procedure, called a biopsy, enables your doctor to examine your breast tissue under a microscope. With close examination, doctors can detect any changes in the tissue.

If you have a lump in your breast, your doctor biopsies the lump to check for cancer.

In some cases, doctors use ultrasound to view the interior of your breast. Ultrasound uses sound waves to create a picture of interior body structures. Your doctor may also order a mammogram or a magnetic resonance imaging scan (MRI). Mammography machines use X-rays to view any changes in your breast, while MRIs use radio waves and powerful magnets to create detailed images of your breast.

Management and Treatment

How is mammary duct ectasia treated?

For many women, mammary duct ectasia resolves on its own with no treatment. Some women find simple care, like warm compresses applied to the breast, is enough to manage symptoms.

If a bacterial infection causes your condition, your doctor prescribes antibiotic medications. Generally, you take antibiotics until the infection subsides, which may be a week or more.

If a milk duct remains blocked despite other treatments, your doctor can remove the inflamed duct surgically.

What complications are associated with mammary duct ectasia?

Left untreated, a bacterial infection causing duct ectasia may cause more widespread infection and tissue damage.

Mammary duct ectasia does not increase your risk for breast cancer.


Can mammary duct ectasia be prevented?

There is no way to prevent mammary duct ectasia. Some research suggests certain lifestyle factors may increase your likelihood of developing this condition. These factors include:

Maintaining a healthy weight, quitting smoking and managing diabetes may all help prevent the development of mammary duct ectasia.

Outlook / Prognosis

What is the prognosis (outlook) for people with mammary duct ectasia?

Most women recover from mammary duct ectasia without treatment. Women who do need treatment usually recover completely, without any complications.

Living With

What questions should I ask my doctor?

If you think you may have mammary duct ectasia, you may have many questions for your doctor, including:

  • How can I treat my condition at home?
  • What signs or symptoms should I watch out for that might indicate my condition is worsening?
  • How will I know my lump is caused by mammary duct ectasia and not by breast cancer?
  • Which treatments will be most effective for my symptoms?

Last reviewed by a Cleveland Clinic medical professional on 04/20/2019.


  • American Cancer Society. Duct Ectasia. ( Accessed 4/22/2019.
  • National Health Service. Mastitis. ( Accessed 4/22/2019.
  • Song L, Li L, Liu B, et al. Diagnostic evaluations of ultrasound and magnetic resonance imaging in mammary duct ectasia and breast cancer. ( Oncology Letters. 2018 Feb; 15(2): 1698-1706. Accessed 4/22/2019.

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