Mesenteric arteriovenous shunt associated with thrombosis of the portal venous system: case report.

We report a rare case of mesenteric arteriovenous shunt associated with thrombosis of the portal venous system. The angiographic features consisted of new vessel formation, thrombosis of the main portal vein, superior mesenteric vein and branches, and early filling of distal mesenteric veins with hepatopetal collateral flow. This phenomenon may be due to new vessel formation within the portal vein thrombosis and active lysis of the thrombus exposing the organizing vessels to the distal superior mesenteric veins.