Prolactinomas in men: clinical characteristics and the effect of bromocriptine treatment.

Thirty-seven men with prolactin (PRL) producing pituitary adenomas were studied to elucidate if patient's delay might cause the predominance of large tumours in men as compared to women in whom microadenomas predominate. We found two clinical subgroups; one presented with short duration of symptoms, dominated by local signs from the growth of notably large tumours, the other exhibited a long history of disease with hypogonadism as the dominating symptom. There was a correlation between tumour size and PRL levels. The age at the time of diagnosis showed no correlation to duration of symptoms, size of adenoma or PRL levels. Four patients with small adenomas, moderate hyperprolactinemia and short duration of symptoms showed signs of hypergonadotropic hypogonadism. Surgery or irradiation, performed in 14 patients, did not normalize PRL levels. Bromocriptine was equally beneficial in the two clinical subgroups, improving clinical symptoms and normalizing PRL levels in all but three patients. The study shows that the predominance of large tumours in men does not depend on patient's or doctor's delay, but on a high frequency of presumably rapidly growing PRL producing tumours. In the majority of patients, these tumours do not give signs of hypogonadism before the tumour is revealed by local signs of tumour growth.