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 developing after non-ischemic tumor enucleation of a small renal cell carci- noma using a microwave tissue coagulator. A 50-year-old Japanese man presented with right flank pain and gross hematuria. The patient had undergone non-ischemic tumor enucleation for right renal cell carcinoma, 2 cm in diameter, 1 month previously. Doppler ultrasound revealed the for- mation of an arteriovenous fistula at the enucleated portion. Transcatheter super-selective occlusion of the feeding artery was successfully performed with two metallic coils. The patient has been fol- lowed up with no sign of recanalization of the fistula. In this case, the tumor was located close to the renal hilus with thick arterial branches around the tumor. Additional microwave coagulations against arterial bleeding from the cutting surface might have been the cause of the fistula forma- tion of this case. Non-ischemic tumor enucleation using a microwave tissue coagulator is a rela- tively easy and secure nephron-sparing surgical procedure. Excessive coagulation, however, should be avoided, since it might be the cause of unexpected postoperative vascular complications.