Adenocarcinomas arising from primary retroperitoneal teratoma in an adult female patient.

Presented herein is a case of primary retroperitoneal teratoma with adenocarcinomatous transformation predominantly composed of signet ring cell carcinoma and intestinal-type adenocarcinoma in a 36-year-old woman. Retroperitoneum is an infrequent location for teratoma in adults and malignant transformation is exceptionally rare. Clinical manifestations, radiological studies, laboratory investigation, and pathological findings of this case are described. To the best of the authors' knowledge, 16 adult cases of primary retroperitoneal teratoma with malignant change have been reported in the literature. Herein is reported the first case of malignant teratoma with prominent component of signet ring cell carcinoma.