Clinical and Imaging Evaluation of Nipple Discharge

Nipple discharge, the spontaneous release of fluid from the nipple, is a common presenting finding that may be caused by an underlying intraductal or juxtaductal pathology, hormonal imbalance, or a physiologic event. Spontaneous nipple discharge must be regarded as abnormal, although the cause is usually benign in most cases. Clinical evaluation based on careful history taking and physical examination, and observation of the macroscopic appearance of the discharge can help to determine if the discharge is physiologic or pathologic. Pathologic discharge can frequently be uni-orificial, localized to a single duct and to a unilateral breast. Careful assessment of the discharge is mandatory, including testing for occult blood and cytologic study for malignant cells. If the discharge is physiologic, reassurance of its benign nature should be given. When a pathologic discharge is suspected, the main goal is to exclude the possibility of carcinoma, which accounts for only a small proportion of cases with nipple discharge. If the woman has unilateral nipple discharge, ultrasound and mammography are frequently the first investigative steps. Cytology of the discharge is routine. Ultrasound is particularly useful for localizing the dilated duct, the possible intraductal or juxtaductal pathology, and for guidance of aspiration, biopsy, or preoperative wire localization. Galactography and magnetic resonance imaging can be selectively used in patients with problematic ultrasound and mammography results. Whenever there is an imaging-detected nodule or focal pathology in the duct or breast stroma, needle aspiration cytology, core needle biopsy, or excisional biopsy should be performed for diagnosis. An excisional biopsy should be carried out with a thorough plan after a complete imaging evaluation. The evaluation of physiologic discharge or galactorrhea is primarily an assessment of endocrine factors.