Case 12-2000

Presentation of Case A 60-year-old man was referred to the hospital because of a pituitary macroadenoma. The patient had been well until three years earlier, when he became impotent and his libido decreased. Two months before his referral to this hospital, his nipples became sore. The prolactin level was 33.6 ng per milliliter (normal range, 0 to 15); the total testosterone level was 306 ng per deciliter (10.6 nmol per liter; normal range, 270 to 1070 ng per deciliter [9.36 to 37.1 nmol per liter]). Magnetic resonance imaging (MRI) revealed a mass, 11 mm in diameter, in the right pituitary . . .