Mature teratoma arising in intraabdominal undescended testis in an infant with previous inguinal exploration: case report and review of intraabdominal testicular tumors in children.

The authors report the youngest case of postoperative intraabdominal mature testicular teratoma in a 5-year-old boy after previous exploration for impalpable testis. A total of 26 cases of intraabdominal testicular tumor in children including our case were reviewed and discussed from both the English- and the Japanese-language literature. The average age was 2.5 years, and, in the 13 children younger than 1 year there were no malignant teratomas, although there was one immature teratoma. Four of these had undergone previous inguinal exploration in which 3 patients except our patient were more than 10 years old. This case report confirms the importance of finding an intraabdominal testis at operation for impalpable testis. Early detection of the testicular location near the internal inguinal ring in these patients supports the hypothesis that the intraabdominal testicular teratoma itself may have been the primary cause of the undescended testis. Furthermore, it is suspected that many of the intraabdominal testicular malignant teratomas in adults may have arisen from these mature testicular teratomas in infants.