Unilateral, spontaneous, bloody, or serosanguinous discharge from a single duct is usually caused by an intraductal papilloma or, rarely, by an intraductal cancer. In either case, a mass may not be palpable. The involved duct may be identified by pressure at different sites around the nipple and at the margin of the areola. Bloody discharge is more suggestive of cancer but usually is caused by a benign papilloma in the duct. In premenopausal women, spontaneous multiple-duct discharge, unilateral or bilateral, is most marked just before menstruation. It often is caused by fibrocystic change. Discharge may be green or brownish. Papillomatosis and ductal ectasia are usually seen on biopsy. If a mass is present, it should be removed. Milky discharge from multiple ducts in nonlactating women presumably reﬂects increased secretion of pituitary prolactin; serum prolactin and thyroid-stimulating hormone levels should be evaluated to detect a pituitary tumor or hypothyroidism. Hypothyroidism may cause galactorrhea. Alternatively, phenothiazines may cause milky discharge that disappears when the medication is discontinued. Oral contraceptive agents may cause clear, serous, or milky discharge from multiple ducts or, less often, from a single duct. The discharge is more evident just before menstruation and disappears when the medication is stopped.
Chronic unilateral nipple discharge, especially if it is bloody, is an indication for resection of the involved ducts. Mammography and ultrasonography are performed to rule out an associated mass. On occasion, ductography may be performed to identify a filling defect before excision of the duct system, but usually this technique is of little value (178). Ductography is not a substitute for excision because it misses multiple lesions and cannot visualize the periphery (181).
Fiberoptic ductoscopy is a technology used to evaluate patients with nipple discharge (182). In 259 patients with nipple discharge, fiberoptic ductoscopy successfully detected intraductal
Erosive Adenomatosis of the Nipple papillary lesions in 92 patients (36%). Office-based, minimally invasive breast ductoscopy with intraductal biopsy is available in some centers (183,184). It was performed for diagnosis in 83 patients with nipple discharge (183). A diagnosis of severe or malignant atypia was established in 21% of patients.
Cytologic examination of nipple discharge or cyst ﬂuid rarely is performed. Cytologic examination usually is of no value but may identify malignant cells (178). Negative findings do not rule out cancer, which is more likely in women older than 50 years of age. In any case, the involved duct—and a mass, if present—should be excised (177,178,180,185). Complete histopathologic evaluation of the involved ductal system is the preferred method of diagnosis, and cytologic assessment should not be relied on for diagnosis.
The usual approach for nipple discharge is surgical excision through a periareolar incision adjacent to the trigger point, the pressure point that elicits nipple discharge (179). A microdochetomy of a single duct or a central duct excision of the major subareolar ducts can be performed under local or general anesthesia. The putative duct can be cannulated, methylene blue can be injected, or a lacrimal probe can be inserted into the duct for localization. A resection of breast tissue for 3 to 5 cm, or until no bloody ﬂuid can be identified in the ductal system, is performed. The patient must be warned of possible skin and nipple loss as a result of compromised vascularity, change in nipple sensation, deformity, inability to breastfeed, and recurrence if only a single duct if removed.