A Boy with 46,XX Karyotype (SRY double-positive) having a Leydig Cell Tumor

Leydig cell tumors are the most common type of testicular sex cord stromal tumors. Presence of Y chromosome is associated with tumor risk in sex development disorder (DSD), however tumor development without Y chromosome are extremely rare. A 16-year-old boy diagnosed with Leydig cell tumor due to a mass in the right testis was referred after the right orchiectomy. In physical examination, left testis was 10 ml, and a labium residue in penoscrotal region with bilateral gynecomastia was present. Karyotype was 46,XX, and SRY was double-positive in FISH analysis. Ifosfamide, carboplatin and etoposide chemotherapy was initiated due to Leydig cell tumor. Here, we report the first pediatric case having 46,XX, SRY double-positive testicular DSD with Leydig cell tumor.