Retroperitoneal teratoma with malignant transformation is a rare condition in adults. Its most common malignant transformation is into a squamous cell carcinoma, but rarely into a mucinous adenocarcinoma. Postoperative treatment of mucinous adenocarcinoma arising from teratomas has not been established due to its rare incidence. Here we present a case of retroperitoneal mucinous adenocarcinoma arising from a teratoma in the presacral area. Operative and postoperative managements are described with a brief review of the literatures.
