A testosterone-producing Leydig cell tumor metastasis during hormonal treatment of prostate cancer.

We describe a patient with a testosterone-producing metastasis discovered during the follow-up of prostate cancer. The patient had a history of a Leydig cell tumor (LCT) in the right testicle for which he underwent radical orchiectomy at the age of 60 years. Within a year after orchiectomy, he was diagnosed with prostate cancer. He received a radical prostatectomy with pelvic lymph node dissection. Due to recurrent prostate cancer, he underwent salvage radiation to the prostatic fossa and pelvic lymph node stations with hormonal treatment for 3 years. After approximately 1.5 years of chemical castration, a significant increase in testosterone level occurred. Further, diagnostic evaluations and surgery revealed a testosterone-producing LCT metastasis in the retroperitoneum.