Vascular anomalies in patients undergoing retroperitoneal lymph node dissection.

382 Background: Anomalies of the renal vessels usually are clinically silent and might depicted during CT scanning of the abdomen for staging purposes of urological malignancies. Awareness of these rare anomalies is crucial especially in patients undergoing staging for germ cell tumors in order to avoid overstaging and unnecessary therapy. We report on the incidence of renal vessel anomalies in an unselected group of patients undergoing retroperitoneal lymph node dissection (RPLND) for testis cancer. Methods: 245 patients with testicular germ cell tumors underwent primary or secondary RPLND following inductive chemotherapy. Prior to RPLND, all patients underwent abdominal staging by CT scans or by MRI in selected cases. CT scans were reviewed with regard to the detection of vascular anomalies of the vena cava inf., renal veins, renal arteries, and iliac vessels. CT findings were correlated with intraoperative findings. Results: Overall, vascular anomalies were encountered in 39 patients (15.9%): retroaortic left renal vein in 10 (4.1%), circumaortic left renal vein in two (0.8%), reduplication of the common iliac vein in one (0.4%), accessory renal arteries in 14 (5.7%), thrombosis of the inferior vena cava in 12 (4.9%) patients with IIC disease. Anomalies of the renal vein were detected in 10 out of 12 (83%), in two cases venous anomalies were falsely diagnosed as lymph node disease in stage I NSGCT. All arterial anomalies were identified preoperatively. CT scan identified caval thrombosis in only eight cases (68%), four cases were identified by an additional MRI of the abdomen. Conclusions: Vascular anomalies are frequently encountered in patients with RPLND for testis cancer and have to be acknowledged during surgery even with negative imaging studies. Retroaortic renal veins represent a potential pitfall of CT imaging resulting in unnecessary therapy; it should be considered in pts with CT suspicious lymph nodes caudal to the renal hilus. IVC thrombosis is associated with advanced disease and is best diagnosed by MRI of the abdomen.