A method for detecting occult Leydig cell tissue of the testis utilizes the determination of plasma testosterone or testosterone production before and after administration of chorionic gonadotropin. The method was applied successfully to the detection of testes in a boy with bilateral cryptorchidism, who had been unsuccessfully explored for testes, and in a true hermaphrodite. It is recommended that testosterone determinations after chorionic gonadotropin be applied to detect testes in prepubertal children with bilateral cryptorchidism, testicular feminization, and ambiguous genitalia.
Levine LS, New MI. Preoperative Detection of Hidden Testes. Am J Dis Child. 1971;121(2):176–178. doi:10.1001/archpedi.1971.02100130130017