A Case of Retroperitoneal Mature Teratoma with Combined Resection of Left Kidney

A 37-year-old woman with the complaint of stomachache was referred to our hospital because a retroperitoneal tumor was detected in an ultrasound study at another hospital. Magnetic resonance imaging showed a poorly enhanced 14 cm tumor in the left retroperitoneal space suggesting a cyst that contained fat and showed calcification. Abdominal dynamic computed tomography revealed left renal vein stenosis and left ovarian vein dilation caused by tumor compression of the renal vein. The tumor was excised together with the left kidney because the renal vein was adhered to the tumor. The resected specimen weighed 1,300 g, and the histological diagnosis was mature teratoma. The patient has experienced no recurrence at eight months after surgery.