[Gynecomastia: effect of prolonged treatment with dihydrotestosterone by the percutaneous route].

Gynaecomastia is a frequent disorder, sometimes painful or psychologically disturbing. Percutaneous dihydrotestosterone (DHT) was used to treat 30 patients with idiopathic gynaecomastia (IG) and 17 patients in whom the condition was associated with hypogonadism. All patients complaining of pain were relieved. Breast enlargement regressed or was substantially reduced in 22 of the IG patients and in all cases with hypogonadism, except those with gonadal dysgenesis. Plasma levels of testosterone and 17 beta-estradiol were significantly lowered in patients with IG as compared with controls. There was a significant increase in plasma DHT levels and in plasma androgen/estradiol ratio in all cases. The beneficial effects of the drug were manifest within 1 to 2 months in responsive patients. These effects may be due to a local and/or systemic activity. It is suggested that this medium-term treatment without side-effects should be tried in all cases of hypogonadism with gynaecomastia and in IG before considering more drastic therapeutic measures.