Post-transplant pelvic arteriovenous malformation in a living kidney transplant recipient.

Arteriovenous malformations are rare vascular anomalies that may be congenital or occur secondary to trauma or surgery. Here, we report a rare case of a pelvic arteriovenous malformation that gradually enlarged after living-donor kidney transplantation. The recipient, a man with end-stage kidney disease from IgA nephropathy, underwent ABO-compatible living kidney transplantation from his father at 6 years prior. A non-contrast computed tomography scan at 3 years post-kidney transplant incidentally revealed a pelvic vascular lesion that progressively enlarged upon serial imaging. Subsequent contrast-enhanced computed tomography suggested a saccular pelvic arteriovenous malformation, prompting further evaluation with selective angiography. Angiography revealed multiple arterial feeders flowing into the right internal iliac vein via abnormal vascular channels. These changes were likely due to ligation and transection of the right internal iliac vein during kidney transplantation, resulting in sac-like dilation and arteriovenous malformation. Endovascular treatment was performed by venously accessing the dilated right internal iliac vein via the left external and internal iliac collaterals, and embolization was successfully achieved using coils and ethanol. Although arteriovenous malformations can result from surgery, this case represents the first reported instance of a pelvic arteriovenous malformation after kidney transplantation. This report highlights a rare and important vascular complication of kidney transplantation.