A Rare Case of Retroperitoneal Immature Teratoma in a Young Adult Male: A Case Report From Eastern Morocco.

Teratomas are classified as germ-cell tumors. They occur more frequently in the gonads, but extragonadal localization can also occur. Retroperitoneal teratomas are rare and require multidisciplinary management. We report the case of a 20-year-old patient who presented with an immature retroperitoneal teratoma. The patient initially underwent a retroperitoneal mass resection, which resulted in positive resection margins and a residual mass observed in post-operative imaging, necessitating treatment with platinum-based chemotherapy. The purpose of this publication is to highlight the characteristics of retroperitoneal teratoma, along with diagnostic criteria and treatment approaches.