A Case Showing the Dilation of the Intra-splenic Artery and Vein Like A-V Malformation

We report a case of dilation of the intrasplenic artery and vein-like A-V malformation without portal hypertension. A 74-year-old man with bloody ascites causedby rupture of a splenic artery aneurysm was found in angiography to have dilation of the intrasplenic artery and vein-like A-V malformation, with arterial stenosis and aneurysm at a peripheral site in the hilus, but no dilation of the splenic vein and varices around the spleen. Time from the start of the contrast injection to portal vein filling was almost within the normal range. We discuss this case, focusing on the hemodynamics of splenic circulation. 1) Portal hypertension induced by congenital A-V malformation had been ameliorated by stenosis of thesplenic artery at the hilus of the spleen. 2) The post-stenotic-dilation mechanism spread from the splenic artery to the splenic vein. 3) Portal hypertensioninduced the aneurysm of the splenic artery and dilation, but arterial stenosis thereafter decreased the blood flow and pressure of the portal vein. Because the man had no hepatic disease, varices around the spleen and the clinical sign of A-Vmalformation at a young age, the second theory may be the most promising. Transcatheter arterial embolization therapy for arterial aneurysm rupture is safe and minimally invasive.