[Sacrococcygeal teratoma of newborn infants; a report of two cases].

Two cases of sacrococcygeal teratoma in female infants are reported. Case 1. A newborn baby with a hemispheric mass on her hip underwent surgery 3 days after birth and the lesion proved to be an immature teratoma. The serum AFP level was very high but became normal one month after the operation. The child also had agenesis of the corpus callosum and arachnoid cysts in right middle fossa. She died after developing shunt infection. Case 2. A newborn baby with a mature teratoma was operated on the day following birth. The tumor was subtotally removed, and there has been no recurrence after 6 months. Sacrococcygeal teratoma in female infants is often associated with agenesis of the corpus callosum and arachnoid cysts. They tend to develop almost at the same time as the teratoma. It is often difficult to determine whether the infant should be treated by chemotherapy or not if the teratoma is immature, especially when it has been totally removed, the serum AFP is normal, and the tumor is pathologically of a low grade.