A nipple discharge, in which fluid comes out of the nipple, is often a normal finding. Many premenopausal women are able to express fluid from the nipple. These benign or physiologic nipple discharges are usually not spontaneous, meaning one has to press or squeeze the nipple for the discharge to come out. They are typically multicolored: greenish, gray, and/or white. The often can be produced from both breasts and come out of multiple duct openings on the surface of the nipple. Physiologic nipple discharges are usually not associated with other findings on clinical breast examination or mammogram.
Certain characteristics raise the possibility that a nipple discharge is a sign of cancer. Spontaneous discharges which come out without any pressure on the breast are more suspicious. They may be seen staining the inside of a bra or other clothes. The color of the discharge is significant: clear watery, clear yellow (serous), blood-tinged (serosanguinous) or bloody nipple discharges are more concerning. Other factors include a discharge from only one breast, particularly if it comes out of a single opening on the nipple, or if pressure on one particular part the areola produces the discharge. A nipple discharge in a woman who is either over 50 years old or postmenopausal is significant. A discharge associated with an underlying mass on clinical breast examination or a mammographic abnormality is more likely to be caused by breast cancer.
If you have a nipple discharge you should see your doctor for an evaluation, particularly if it is spontaneous, comes from a single duct, is bloody, clear or yellow, is associated with a lump, you are >50 or postmenopausal, or the discharge persists after your next menstrual cycle if you are premenopausal.
You may be referred to a breast surgeon for an evaluation. Your breast surgeon will take a detailed history about the characteristics of the discharge, any other breast symptoms, breast cancer risk factors and general medical history. A clinical breast examination will be performed. For a woman who is thirty or older with a nipple discharge, a mammogram will usually be done, not only to get more information about the discharge, but also to be see if any other findings have developed elsewhere in either breast. An ultrasound may be performed to see if the underlying cause of the discharge can be identified, such as benign findings like a cyst or duct ectasia. If a solid mass is seen on ultrasound, a biopsy of the mass can be performed. A sample of discharge fluid can be sent for analysis, but is not usually helpful since it will appear normal in 50% of nipple discharges associated with breast cancer. If the discharge is clinically significant, but there are no findings on ultrasound, a breast MRI may be performed; ductograms (in which dye is instilled in the duct to look for masses) are rarely necessary.
If an abnormality associated with the discharge can be seen on mammogram, ultrasound or MRI, a needle biopsy may be performed. Sometimes a specific type of breast biopsy called a duct excision is performed to make a diagnosis. With this surgical procedure, while under anesthesia, dye is injected into the duct opening, and the ducts associated with the discharge are removed through a small incision. Many clinically significant discharges are caused by benign intraductal papillomas. Unfortunately needle biopsies cannot distinguish benign papillomas from papillary breast cancer, so if it appears likely that the discharge is caused by a papilloma, a surgical biopsy could be considered to avoid a two-step evaluation with both needle biopsy and surgical biopsy. Nipple discharges may also be caused by duct ectasia, in which the ducts beneath the nipple become dilated and distended with fluid, or other types of fibrocystic changes.