Renal arteriovenous fistula developing after tumor enucleation using a microwave tissue coagulator

With the increase in detection of incidental renal cell carcinoma, nephron- sparing surgery for small renal cell carcinomas is now recognized as one of the surgical options. We report a case of renal arteriovenous fistula deve loping after non-ischemic tumor enucleation of a small renal cell carcinoma using a microwave tissue coagulator. A 50-year-old Japanese man presented with right flank pain and gross hematuria. The patient had undergone non-is chemic tumor enucleation for right renal cell carcinoma, 2 cm in diameter, 1 month previously. Doppler ultrasound revealed the formation of an arterio venous fistula at the enucleated portion. Transcatheter super-selective occ lusion of the feeding artery was successfully performed with two metallic c oils. The patient has been followed up with no sign of recanalization of th e fistula. In this case, the tumor was located close to the renal hilus wit h thick arterial branches around the tumor. Additional microwave coagulatio ns against arterial bleeding from the cutting surface might have been the c ause of the fistula formation of this case. Non-ischemic tumor enucleation using a microwave tissue coagulator is a relatively easy and secure nephron -sparing surgical procedure. Excessive coagulation, however, should be avoi ded, since it might be the cause of unexpected postoperative vascular compl ications.