Arteriovenous malformation in a kidney allograft

Arteriovenous aneurysms may be congenital (arteriovenous malformation, AVM) or acquired (arteriovenous fistula, AVF). AVFs after a renal transplant biopsy are seldom, but well recognized, usually harmless complications [1]. Congenital AVMs are usually of the cirsoid (racemose) type [2], characterized by a tangle of tortuous vessels of small diameter, with multiple varix-like communications between the artery and the vein, arteriovenous shunting and lack of intervening capillaries. AVMs may be associated with multiple intraparenchymal haemorrhagic foci, which are caused by ruptures of the vessel walls. Here we describe a case of spontaneous renal AVM in a kidney transplant patient who had undergone deceased-donor renal transplantation in 2005 for Alport syndrome and after <3 years presented with progressive renal failure. Allograft nephrectomy revealed classic cirsoid type congential AVM. A search of the literature did not yield any reports of congenital AVM in a renal allograft.