Abstract
A 22-year-old male patient with Down syndrome was referred to our hospital with a vast left testicular mass. He underwent a left radical inguinal orchiectomy, and a histopathological examination of the mass showed a yolk sac tumor invading the epididymis. The patient was discharged in a satisfactory condition. Sixteen days later, the patient presented again complaining of lower limb weakness. Magnetic resonance imaging of the spine showed metastatic lesions compressing the dorsal spine, and he underwent emergency surgical decompression. The histopathology of the metastatic lesions revealed a yolk sac subtype which was identical to his primary testicular tumor.