Leydig cell tumor after treatment for Ewing's sarcoma.

Leydig cell tumors account for 3% of testicular tumors and have never been reported after treatment for Ewing's sarcoma. We report the unusual occurrence of a patient who developed a Leydig cell tumor of the testis 18 years after successful treatment for Ewing's sarcoma. Additional monitoring for second malignancies may become appropriate as long-term survival continues to improve for patients with Ewing's sarcoma.