Endocrine Abstracts

Introduction: It is accepted that hyperprolactinaemia associated with microprolactinoma may prove self-limiting in 25–30% women, and there is some suggestion from series of mixed gender that the same may be true in men.

Methods: We have therefore reviewed the outcome in all men with microprolactinomas managed at the Department of Diabetes and Endocrinology, City Hospital, Nottingham, between 1994 and 2002. All had sustained and previously untreated hyperprolactinaemia (>600 mIU/l). Macroprolactinoma and drug-induced disease were excluded.

Results: There were 10 men with a median age of 55.5 years (range 40–70). Pituitary imaging prior to treatment (MRI/CT) revealed microadenomas in 2 but was normal in 8. Other pituitary function was normal in all cases. Initial prolactin (confirmed elevated in at least one other specimen) was 1305 mIU/l (624-26000). Median serum testosterone was 7 nmol/l (3.7–17.6) (reference range 8–27 nmol/l). Other pituitary function was normal. Two (baseline PRL 624, 784) opted not to be treated, and serum prolactin fell to, and remained, within the reference range in both during 75 and 30 months of follow up. The remaining 8 received dopamine agonist therapy (bromocripitine, quinagolide or cabergoline) in conventional modest doses. Therapy was discontinued irregularly and serum prolactin monitored each 6 to 12 months. Treatment was permanently discontinued in three after 47, 48 and 50 months and most recent serum prolactin (measured after an interval of 27, 29 and 35 months, respectively, was 817, 558 and 893 mIU/l. Pre-treatment prolactin concentrations in these three were 1300, 4600 and 1310. Treatment was discontinued in a fourth man after 78 months and serum prolactin was 300 mIU/l when measured one month later.

Conclusion: These data suggest that idiopathic hyperprolactinaemia (with or without demonstrable microadenoma) may prove self-limiting in men, but the possibility needs to be substantiated in a larger cohort.