A case of immature teratoma originating in intra-abdominal undescended testis in a 3-month-old infant.

Teratomas in an undescended testis are rare in infants. This report was the youngest case of immature teratoma originating in intra-abdominal undescended testis. A 3-month-old infant with cryptorchism was seen because of an asymptomatic palpable mass in the right abdomen. Ultrasonography and computed tomography revealed a multicystic large tumor with focal calcifications in the right side and serum tumor markers within normal limits. Complete resection of the tumor was performed and the histopathological diagnosis was made as immature teratoma of the right testis. Because retroperitoneal lymph nodes metastasis was observed in 3-month follow-up postoperatively, retroperitoneal lymphadenectomy and chemotherapy including bleomycin, etoposide, and cisplatin were performed. Presently, the infant has been free of recurrence for 3 years. We suggest that nonpalpable testis should undergo a careful evaluation and prompt resolution and that the subsequent finding of an intra-abdominal mass should make us think on the possibility of intra-abdominal testicular germ cell tumor. Postoperative adjuvant chemotherapy in combination with complete resection of the tumor is necessary for pediatric immature teratomas originating in intra-abdominal undescended testis.