Testosterone-secreting gonadotropin-responsive adrenal adenoma and its treatment with the antiandrogen flutamide

A 55-year-old woman with virilization had an appreciably elevated testosterone level, which was not suppressed by dexamethasone, but was increased by stimulation with human chorionic gonadotropin (hCG). Ultrasonography and computed tomography revealed an adenoma 2.5-3.0 cm in diameter in the right adrenal gland. The patient was treated with the antiandrogen flutamide in a daily dose of 500 mg for 4 months. A substantial regression of her hirsutism was observed during flutamide administration, but the serum testosterone level remained high. Right adrenalectomy was performed. Histologically, the tumor proved to be an adrenocortical adenoma of zona reticularis type. The adenoma tissue contained specific hCG receptors (187 fmol/g). The steroid concentration in the tumor tissue was examined by means of high pressure liquid chromatography-radioimmunoassay (HPLC-RIA). A significantly increased testosterone content was detected, and the levels of its precursors, androstenedione and dehydroepiandrosterone, were also elevated. Following adrenalectomy, serum testosterone concentration decreased to the normal level. The mechanism of the inappropriate regulation in the testosterone production of the adrenal tumor has not been fully elucidated.