The diagnosis of Leydig cell tumors in childhood.

We report the clinical and hormonal findings in two boys with isosexual precocity secondary to Levdig cell tumor of the testis. The hormonal profile at the initial evaluation was quite different in the two cases suggesting differences in steroid biosynthesis by the tumors. These differences indicate that a dexamethasone suppression test may be required to differentiate between Leydig cell tumors and congenital virilizing adrenal hyperplasia with adrenal rest tissue located within the testes.