Primary medical therapy of micro- and macroprolactinomas in men

The presentation and long-term therapeutic responses of PRL-secreting pitui tary tumors in men have been only partially studied. Gender-specific differ ences in tumor size at clinical presentation and possible differences in tu mor biology in men compared to women make it important to determine treatme nt outcomes of male patients with prolactinomas. We performed a retrospective review of men with prolactinomas medically man aged at Massachusetts General Hospital between 1980 and 1997. We identified 46 male patients with prolactinomas managed with medical therapy alone. Tw elve patients had microadenomas, defined as a serum PRL level greater than 15 ng/mL and a normal pituitary scan or a tumor smaller than 1 cm. Thirty-f our patients had macroprolactinomas, defined by a serum PRL greater than 20 0 ng/mL and pituitary adenoma larger than 1 cm. Bromocriptine, quinagolide, and/or cabergoline were administered as medical therapy. AU patients had a t least one follow-up visit, and the most recent serum PRL measurement afte r initiating dopamine agonist therapy was reported. Baseline clinical characteristics for patients with macroprolactinomas and microprolactinomas showed a larger proportion of patients with macroprolact inomas reporting a history of headache (74% vs. 0%), whereas the prevalence of sexual dysfunction and testosterone deficiency was similar between the two groups. Median serum PRL at presentation was 99 ng/mL, (range, 16-385 n g/mL) vs. 1415 ng/mL (range, 387-67,900 ng/mL), in the microprolactinoma an d macroprolactinoma groups, respectively. A normal PRL level was achieved in a similar percentage of men with micropr olactinomas vs, macroprolaetinomas (83% vs. 79%, respectively). Although th e majority of patients in both groups were treated with bromocriptine, a co mparable number of patients with microprolactinomas vs. macroprolactinomas achieved a normal PRL level with cabergoline therapy. The response rates fo r bromocriptine and cabergoline were similar in both groups. No patient wit h a microprolactinoma required hormone replacement therapy, in contrast to patients with macroprolactinomas, who required thyroid, testosterone, and/o r glucocorticoid replacement therapy. No patient had evidence of an increas e in tumor size during therapy. In summary, me investigated the clinical presentation and treatment outcome in men with prolactinomas. We found that normalization of serum PRL levels occurs in approximately 80% of men with prolactinomas. Of importance, dopa mine agonist administration yielded similar biochemical remission rates in men with microprolactinomas and macroprolactinomas.