Hyperprolactinaemia in males: a heterogeneous disorder.

BACKGROUND: The literature suggests that men with prolactinomas typically present with pressure effects of large pituitary tumours and/or the clinical features of hypogonadism. A definitive study of the clinical features of hyperprolactinaemia in males is, however, lacking

AIMS: To identity the clinical, biochemical and radiological features of hyperprolactinaemia in males.

METHODS: Retrospective review of the case notes of 53 adult males with prolactinoma or idiopathic hyperprolactinaemia diagnosed 1980-1995.

RESULTS: The mean age of the patients was 41 years (range 19-75). The presenting symptom was endocrine in nature in 57% of patients (loss of libido/potency 47%, gynaecomastia 6%, galactorrhoea 2%, sparse beard growth 2%), pressure effects of pituitary tumour in 28% (headache 13%, visual loss 13%, diplopia 2%), while 15% of patients presented incidentally. On physical examination, galactorrhoea was present in 8% of patients, gynaecomastia in 23% and abnormally sparse body hair in 21%. Testicular volume was normal (> or = 15 mL) in all but two patients, both of whom had evidence of delayed pubertal development. Visual loss was present in 17% of patients. Serum prolactin ranged from 800 to 1.7 million mU/L (median 20,000 mU/L, reference range < 500), and serum testosterone from 0.7 to 19.3 nmol/L (mean 7.8 nmol/L, reference range ten-35). Pituitary imaging by computed tomography (45%) or magnetic resonance imaging (55%) demonstrated macroadenomas in 70% of patients, microadenomas in 15%, and no detectable tumour in 15% of subjects. On bromocriptine treatment (47 subjects), 89% of patients reported improved sexual function. Follow up imaging in 36 patients with abnormal scans at presentation revealed tumour shrinkage in 89% of cases.

CONCLUSIONS: Hyperprolactinaemia in males is a heterogeneous disorder. The majority of patients have prolactin-secreting macroadenomas, but there is wide variation in presenting symptoms, physical signs and results of biochemical and imaging investigations. Bromocriptine treatment is associated with symptomatic improvement and a reduction in tumour size in most cases.