Unilateral malignant leydig cell tumor of testis in a patient with contralateral cryptorchidism.

Received October 2007 Accepted June 2008 INTRODUCTION Leydig cell tumors (LCTs) are the most common stromal tumors, accounting for 3% of all testicular neoplasms.(1) Approximately, 3% of the LCTs are bilateral.(1) They may be hormonally active, leading to either feminizing or virilizing syndromes. About 10% of them are malignant.(1) The diagnosis of a malignant LCT is not always easy, because no definite histological criteria exist for malignancy. About 20% of the patients present already with metastases, while 40% of them will develop secondary foci within 2 years.(1,2) Cryptorchidism is a well-established epidimiological risk factor of testicular germ cell cancer; however, data regarding a possible association with sex cordstromal testicular tumors are scarce. (2) Hereby, we present a rare case of unilateral malignant LCT in a patient with a history of contralateral cryptorchidism.