[Testicular leydig cell tumor in a child: a case report].

A 7-year-old boy was admitted to the department of pediatrics in our hospital with the complaint of sexual precocity manifested by a growth spurt, penile enlargement and pubic hair development. He was referred to our department because of the enlarged left testis. The diagnosis of Leydig cell tumor of the left testis was suggested by hormonal laboratory data and testicular ultrasonographic investigation. Left orchiectomy was performed. The histological examination revealed the characteristics of Leydig cell tumor. Twenty-four cases of testicular Leydig cell tumor reported in the Japanese literature until 1988 are clinically analyzed. We discuss the usefulness of ultrasonography in detecting and localizing the tumor.