Abstract
A 59-year-old woman was admitted to our hospital because of right upper abdominal tumor. She had a history of cafe-au-lait spots and skin tumors on her entire body from infancy. Abdominal CT and ultrasonographic findings indicated that the tumor was 4.0×4.0 cm in size on the right kidney and that the wall was partially calcified. We diagnosed the tumor as a retroperitoneal teratoma, and performed excision. There was viscous yellow liquid and hair within the tumor. Histological diagnosis was mature teratoma. Retroperitoneal teratoma in an adult is very rare, and has been reported in 31 cases in Japan. Computed tomography is useful for the diagnosis. Whether it is malignant or benign cannot be verified except by histological findings. However 31% of cases were malignant, so we should emphasize the importance of surgical removal and the early diagnosis.
