Circumaortic left renal vein: report of a case.

Circumaortic left renal vein is an uncommon anomaly which has not been previously reported in Taiwan. We describe a case of circumaortic left renal vein in a 15-year-old girl who presented with intermittent hematuria. Angiogram revealed double left renal veins in the form of a venous collar. Computed tomography depicted the preaortic and retroaortic left renal veins clearly. In a survey of hematuria, circumaortic renal vein should be taken into consideration in a differential diagnosis, and an appreciation of the specific radiologic findings can help to establish the diagnosis easily. In addition, preoperative recognition of this uncommon anomaly is of supreme importance in a retroperitoneal operation in order to avoid massive bleeding.