Mammary duct ectasia

Mammary duct ectasia (ek-TAY-zhuh) occurs when a milk duct beneath your nipple becomes wider (dilated), the duct walls thicken and the duct fills with fluid. The milk duct can then become blocked or clogged with a thick, sticky substance. The condition often causes no symptoms, but some women may have nipple discharge, breast tenderness or inflammation of the clogged duct (periductal mastitis).

Your chance of developing mammary duct ectasia — with or without inflammation — increases with age. Mammary duct ectasia usually improves without treatment. However, if symptoms persist despite self-care measures, you may need antibiotics or possibly surgery to remove the affected milk duct.

Though it's normal to worry about any changes in your breasts, mammary duct ectasia and periductal mastisis aren't risk factors for breast cancer.

Symptoms Causes Complications

Although mammary duct ectasia often doesn't cause signs and symptoms, you may experience:

  • A dirty white, greenish or black nipple discharge from one or both nipples
  • Tenderness in the nipple or surrounding breast tissue
  • Redness of the nipple and sometimes the surrounding area
  • A breast lump or thickening near the clogged duct
  • A nipple that's turned inward (inverted)

A bacterial infection called mastitis also may develop in the affected milk duct and cause inflammation in the area around the nipple (areola) and fever. Signs and symptoms of mammary duct ectasia usually improve on their own.

When to see a doctor

It's important for your doctor to promptly evaluate any changes in your breasts to rule out breast cancer. If you have symptoms of mammary duct ectasia — especially unusual nipple discharge — make an appointment with your doctor for evaluation.

© 1998-2015 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of use