“Nipple discharge is benign in most instances and is the third most common breast-related complaint, after breast pain and breast mass,” says an article in the Canadian Medical Association Journal (CMAJ May 19, 2015).
About 50 per cent of women in their reproductive years have nipple discharge, which are physiological. This kind of discharge is usually from both breasts, milky, green or yellow fluid expressed from multiple nipple duct openings and often associated with nipple stimulation. Usually these patients do not require surgery if the ultrasound and mammogram is normal. Discharge may spontaneously disappear.
Nipple discharge you should be worried about are spontaneous and often from one breast. It may arise from a single duct or be associated with a breast lump or new skin changes. It can be bloody, serous (clear thin plasma fluid), green or black.
About 15 per cent of these patients will have breast cancer. About 50 per cent of these patients will have benign intraductal papilloma (benign growth in the duct), and 20 per cent will have ductal ectasia.
Ductal ectasia of the breast (also known as mammary duct ectasia or plasma cell mastitis) is a condition in which the lactiferous breast duct becomes blocked or clogged. This is the most common cause of greenish discharge. Mammary duct ectasia can mimic breast cancer. It is a disorder of peri- or post-menopausal women.
Intraductal papillomas are benign growths of the nipples in women close to menopause. They are usually single. Generally they are not seen on mammography. Surgical excision is indicated to rule out malignancy. These papillomas are the most common cause of bloody nipple discharge.
What can be done for women with nipple discharge?
Women with nipple discharge should be investigated. Mammography (sensitivity may be decreased in younger patients) and retroareolar ultrasonography should be performed in all cases of pathologic nipple discharge. Galactography, and more recently, magnetic resonance imaging, can be helpful in identifying an involved duct or papilloma. Patients with a palpable mass or a mass identified on imaging should undergo needle biopsy to exclude carcinoma, says the CMAJ article.
Milky discharge in patients who are not pregnant or lactating (galactorrhea) is often due to medications. Milky nipple discharge from both breasts is appropriate during pregnancy and lactation, and it can last up to one year after delivery or after breast-feeding has stopped.
In patients who are not pregnant but are lactating should have prolactin levels checked to exclude endocrine disorder (> 20 ng/mL). Medications such as:
- Psychotropics, antihypertensives (e.g., reserpine, methyldopa, verapamil),
- Opiates, prokinetics (e.g., metoclopramide) and
- H2-blockers (e.g., cimetidine) can cause galactorrhea.
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