Late recurrence with malignant degeneration of testicular teratoma. Case report.

Radical orchiectomy was performed on a 25-year-old man for benign mature teratoma. A synchronous without change 3 cm retroperitoneal mass was followed for five years. The mass enlarged and became symptomatic twelve years after orchiectomy. Excision of the mass revealed a non-seminomatous germ cell tumor. Possible explanation is malignant degeneration of the teratomatous elements. Testicular teratomas should be treated as potentially malignant non-seminomatous tumor.