Renal Arteriovenous Fistula and Fibromuscular Hyperplasia

An essentially asymptomatic patient with a continuous abdominal bruit was investigated and found to have a right renal arteriovenous fistula and bilateral renal artery fibromuscular hyperplasia. The various causes of intrarenal artery fistula, congenital and acquired, are considered. It is suggested that rupture or erosion of an aneurysm characteristically observed in fibromuscular hyperplasia may possibly have been responsible for the renal arteriovenous fistula in this patient. There is histologic evidence to suspect that variants of fibromuscular hyperplasia, the renal artery fibroplasias, may have been present but unrecognized in cases of intrarenal arteriovenous fistula previously reported and classified as congenital. Rupture of an aneurysm associated with these fibroplasias may have created the renal fistulas. Thus, the renal artery fibroplasias may be a heretofore unrecognized cause of renal artery fistula.