Giant idiopathic renal arteriovenous fistula requiring urgent nephrectomy.

Idiopathic renal arteriovenous fistulas (AVFs) with acute hemorrhage are exceedingly rare. However, a rare entity such as a renal AVF may be overlooked and have disastrous consequences, requiring an urgent management decision between endovascular or surgical treatment. We report the case of a 61-year-old man, who presented with painless gross hematuria and clot retention. Computed tomography revealed a giant renal arteriovenous malformation, in the absence of any clinical stigmata such as hypertension or congestive heart failure. Gross hematuria resulted from AVF erosion into the collecting system. Given the size of the AVF, endovascular coil embolization was attempted but deemed too risky, necessitating urgent nephrectomy.