Angiographic Findings in Patients with Autoimmune Pancreatitis

Abstract

Editor: I read with great interest the article by Dr Sahani and colleagues in the November 2004 issue of Radiology (1). They analyzed in detail imaging findings in patients with autoimmune pancreatitis. They reported that homogeneous enhancement of the enlarged pancreas with absence of vascular enlargement at computed tomography (CT) was helpful in the differentiation of autoimmune pancreatitis and pancreatic carcinoma. In our angiographic study, however, abnormalities were detected in seven of 13 patients with autoimmune pancreatitis (54%), with irregular narrowing of the anterior superior pancreaticoduodenal artery, posterior superior pancreaticoduodenal artery, and transpancreatic artery, which was evident in seven (54%), four (31%), and two (15%) of 13 patients, respectively. Deviation of the portal or splenic vein was observed in 31% of cases, and these veins were poorly opacified, with collateral veins evident because of stenosis or obstruction in 23% (2). One of the characteristic histologic findings of autoimmune pancreatitis is obliterative phlebitis with lymphoplasmacytic infiltration and proliferation of fibroblasts in and around the walls of the veins, sometimes involving the portal vein (3). In addition, duplication of the internal elastica and intimal thickening are occasionally observed in the small arteries (4). The presence of irregular narrowing of the pancreatic arteries, similar to encasement sometimes detected in pancreatic carcinoma, and stenosis or obstruction of the portal vein could result from the histologic changes described before. Moreover, deviation of the portal veins could be secondary to pancreatic enlargement. These angiographic findings can cause confusion in the diagnosis of autoimmune pancreatitis.