[Simultaneous bilateral testicular tumors with different cell types: a case report].

A 26-year-old man presented with a painless mass in the right scrotum. Physical examination revealed another smaller mass in the left testis. The patient underwent right radical orchiectomy and enucleation of the tumor in the left testis, followed by radiotherapy for right iliac and para-aortic lymph nodes up to a total dose of 30 Gy. Histology proved typical seminoma of the right testis and mature teratoma in the left testis. Imaging study including abdominal CT and chest X-ray and prompt lowering of beta-HCG level within the normal limit after surgery confirmed the diagnosis of stage I disease. Human leukocyte antigen (HLA)-A24 was identified in this case, suggesting its potential association with bilateral testicular tumor. He is now leading an uneventful life without recurrence of the disease at 30 months after surgery.