An 84-year-old man presented with a two-month history of bilateral breast enlargement. Left nipple discharge began 2 1/2 weeks before presentation. He had no discharge from his right nipple. The milky, beige discharge occurred daily, most notably in the early morning and evening, and sometimes contained bright red blood. It was nonpurulent. The patient reported intermittent tenderness in his breasts but had no other symptoms, including fever, chills, night sweats, unexpected weight loss, fatigue, or change in libido or sexual function. He did not have a history of similar symptoms, steroid use, or hormone therapy. The patient's medical history included atrial fibrillation, anticoagulation, hypertension, chronic heart failure, and arthritis treated with long-term opiate use.

Physical examination revealed bilateral gynecomastia that was more pronounced on the left side. A 1-cm mass was palpated at the 10-o'clock position, about 2 to 4 cm from the left nipple. Another 1-cm mass was palpated at the 4-o'clock position, about 1 cm from the same nipple. One drop of bright red blood was expressed from the left nipple (Figure 1). No other masses were detected in either breast, and no axillary lymphadenopathy was palpated.