Peripancreatic vascular involvements of autoimmune pancreatitis

Background and Aim: Although peripancreatic vascular lesions are occasionally encountered in autoimmune pancreatitis (AIP), there are few reports focusing on these involvements. We aimed to investigate the peripancreatic vascular involvements associated with AIP. Methods: We retrospectively analyzed 54 AIP patients who met the International Consensus Diagnostic Criteria for AIP between July 2003 and October 2010. All of the 54 patients were subjected to multiphasic multidetector computed tomography, and the prevalence, location and prognosis of peripancreatic vascular involvements were investigated. Results: Of the 54 AIP patients, 24 (44.4%) exhibited involvements in the form of peripancreatic vascular lesions (stenoses of the splenic vein in 22 and of the superior mesenteric-portal vein in 13, development of perigastric collateral circulation in 18, gastric varices with a red color sign in one and thrombosis inside the portal vein in one). Diffuse-type AIP was associated with a significantly higher prevalence of vascular involvements compared with focal-type AIP (P=0.033). A total of 14 out of 16 patients who underwent corticosteroid treatment showed improvement in vascular lesions. One case followed up without corticosteroid treatment and presenting an obstruction of the splenic vein exhibited involvements in the form of an infarction and hemorrhagic cysts of the spleen and ultimately underwent distal pancreatectomy and splenectomy. Conclusions: Autoimmune pancreatitis patients show a high prevalence of peripancreatic vascular involvements. Thus, patients with vascular involvements are suitable candidates for steroid therapy with evaluation of its potential merits and demerits, even if they are asymptomatic.