It can be quite worrisome for women who experience fluid coming from the nipple, otherwise known as nipple discharge. All new or changing occurrences of nipple discharge should be discussed with your primary care provider. That being said, cancer is NOT the most common cause of nipple discharge.
The previous article discussing nipple discharge is focused on women who have not yet undergone imaging evaluation of the discharge. The purpose of this article is to provide more information for women who have been evaluated for nipple discharge and have been told that the cause of the discharge is not cancer.
To review: nipple discharge is any fluid that comes out of the milk ducts through the nipple. This is a normal and expected occurrence during breastfeeding but may be alarming at any other time. Nipple discharge can vary widely in color. The most common colors encountered are yellow, green, brown, black, white, clear, and red (or bloody). Nipple discharge can occur from one breast in multiple ducts or just one duct, or in both breasts. Finally, discharge may occur with or without nipple stimulation including squeezing or repeated chafing from clothing. We DO NOT recommend squeezing your nipples to evaluate for possible nipple discharge. Not only is discharge that occurs only with manipulation not as concerning for cancer, but you also risk damaging the ducts which can result in bleeding; this scenario will only confuse the picture for the doctors managing your care.
Even if the mammogram and ultrasound appearance of the breast/s is/are normal, there are specific discharge characteristics we are looking for that will prompt further imaging evaluation with breast MRI. This is because breast cancer and the non-cancerous breast mass papilloma will result in a very specific type of nipple discharge. Although a papilloma is not considered cancer, it does have the potential to harbor a small focus of cancer or can potentially turn into cancer. Therefore, if a diagnosis of papilloma is made with core needle biopsy, this should be further evaluated by a breast surgeon to determine if the mass should be surgically removed.
Nipple Discharge Characteristics
Here are the discharge characteristics that will likely prompt additional imaging:
- Color: clear and completely colorless OR bloody
- Occurs from a single duct only in one breast
- Occurs without nipple stimulation (squeezing or chafing of the nipples are both forms of stimulation). This is referred to as spontaneous discharge.
It is not a requirement for the discharge to meet all three conditions for the radiologist to consider additional imaging evaluation. Conversely, we do not further evaluate all women who meet just one of these conditions. There will be variability in recommendations based on the description you provide of the discharge, your personal breast cancer risk, age, and breast density as seen on mammography.
Often, women who are evaluated for nipple discharge are told the diagnostic mammogram and ultrasound are negative for cancer as the cause of the discharge. Does this mean with 100% certainty that cancer is not present? No way– nothing in breast imaging is absolute. You can be reassured that the nipple discharge is almost certainly not related to breast cancer. However, a small developing cancer may be present in your breast that is not yet visible on the mammogram. This is why continued annual screening mammography, performing a monthly self-breast exam, and discussing any new breast symptoms with your physician are vital components to maintaining optimum breast health.
In the setting in which a patient has been told that the mammogram and ultrasound are negative and that no additional imaging is necessary to evaluate the nipple discharge, what could be causing the benign nipple discharge? By far the most common cause of nipple discharge is duct ectasia. Duct ectasia is a condition in which the milk ducts dilate or enlarge. Fluid may then collect within the dilated ducts. When enough fluid builds up within the duct some of the fluid will be expressed through the nipple. Other non-cancerous causes of nipple discharge include infection, trauma to the milk ducts, and certain medications.
Unfortunately, nipple discharge is not always treatable. If the discharge is the result of an infection, successful treatment of the infection should resolve the discharge. If you are taking a medication known to cause nipple discharge, discontinuing the medication should also resolve the discharge. If discharge due to duct ectasia occurs from only one duct (the discharge is coming out of a single hole in the nipple of one breast), surgical removal of the duct is an option. Duct ectasia resulting in discharge from multiple ducts is problematic and may not be curable. Symptomatic control may be the best your physician can offer in this situation.