Hyperprolactinaemia in males: a heterogeneous disorder

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

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

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

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.

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.