Virilizing Testicular Tumor: In Vivo Studies of Steroid Secretion

Findings in a six-year-old boy with a virilizing tumor of the left testis are presented. His bone age was 14 years. Serum testosterone (5.9 nglml), urinary 17-ketosteroid (29 mg/24 hr), and pregnanetriol (14 mg/24 hr) excretion was elevated. These values were not suppressed after the administration of dexamethasone. Spermatic-peripheral vein concentration differences showed that the tumor secreted 17-hydroxy-pregnenolone, dehydroeplandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, estrone, estradiol, 11-desoxycortisol, and corticosterone. The tumor did not secrete cortisol. Electron microscopy study of the tumor revealed a dimorphic population of light and dark cells with many features seen in Leydig cell tumors. However, these were not distinct from those of adrenal rest tumors. Reinke crystalloids were not found. True precocious puberty developed five months after tumor removal, ie, the right testis increased in size, and serum gonadotropins increased. Seven months after tumor removal, the patient was demonstrated not to have impaired cortisol synthesis, ie, urinary 17-hydroxysteroids increased from 1.8 to 38.0 mg/24 hr In response to adrenocorticotropic hormone (ACTH) administration. The differential diagnosis of virilizing testicular tumors lies between Leydig cell adenoma and adrenal rest tumor in California congenital adrenal hyperplasla. The demonstration that the patient did not have Impaired cortisol synthesis is consistent with his tumor being a Leydig cell adenoma.