Testicular Yolk Sac Tumor and Mature Teratoma: Synchronous Bilateral Occurrence in an Infant.

Yolk sac tumor (YST) is a rare malignancy typically occurring in children. However, bilateral testicular YSTs are a quite rare situation, which can occur metachronously or synchronously with same histologic type, as well as different histology. We present a case of synchronous YST of the left testis and mature teratoma of the right in a 7-month-old infant treated with testis-sparing surgery at right testis and high radical orchiectomy at left. By follow-up of 28th month, no atrophy, or residual tumor in right testis and no recurrence or evidence of disease in left scrotum was found.