Symptomatic osteoporosis in a man with hyperprolactinemic hypogonadism.

A 66-year-old man presented with height loss, back pain due to an L4 vertebral compression deformity, and marked osteopenia shown by radial photon absorptiometry. The patient had small testes and a long history of infertility and impotence. Plasma testosterone was low (130 ng/dL; normal, 300 to 1000 ng/dL) with marked elevation of serum prolactin (590 ng/mL; normal, 0 to 15 ng/mL). High-resolution computed tomography showed an invasive pituitary macroadenoma with a secondary empty sella turcica. Bone histomorphometry showed low-normal trabecular bone volume with normal formation and resorption indices. The patient was treated with calcium carbonate supplements, testosterone replacement, and bromocriptine mesylate without subsequent progression of the osteoporosis. This first report of hyperprolactinemic hypogonadism in a man who presented with overt osteoporosis shows the importance of evaluating gonadal function in all osteoporotic men.