A 60-years old patient was admitted for mamillary pain for several weeks, without galactorrhea. Erectile dysfunction had been present for several years but diminished libido had developed only recently. Ultrasonography of the mamillary gland was not definite for gynecomastia but repeated serum prolactin concentrations were elevated 5-fold the upper limit of normal. Furthermore serum level of testosterone was decreased and levels of luteinizing hormone and follicle-stimulation hormone were within normal range. Magnetic resonance imaging (MRI) of the pituitary gland could not identify a tumoral mass. In review of the laboratory features and the absence of a tumoral mass on MRI, idiopathic hyperprolactinemia was diagnosed and therapy with a dopamine-agonist was started.