Renal arteriovenous malformation and venous thrombosis: a tumour-like presentation.

Renal arteriovenous malformation is a primarily congenital renal vascular abnormality. It is usually diagnosed incidentally on imaging, and the most common subtype is 'cirsoid', consisting of multiple, enlarged arterial feeders interconnecting with draining veins. We present a 74-year-old woman with an incidental finding of what was at first considered a hypervascularised kidney tumour but turned out to be a left intrarenal arteriovenous malformation associated with a left renal vein thrombosis. Selective endovascular embolisation was performed. The cause-consequence relationship between the arteriovenous malformation and the thrombosis is unique. To our knowledge, no such case has ever been reported.