title: Comparison of radiological and histological findings in autoimmune pancreatitis.
abstract: OBJECTIVE
  Autoimmune pancreatitis displays radiological findings that are sometimes difficult to differentiate from pancreatic carcinoma. To understand the essential radiological features of autoimmune pancreatitis (AIP), we compared imaging and histological findings in resected AIP specimens.
  
  
  METHODS
  Findings of ultrasonography, computed tomography, endoscopic retrograde cholangiopancreatography and angiography were examined retrospectively for 6 patients who underwent pancreatoduodenectomy on suspicion of pancreatic carcinoma, and compared with histological findings of the resected specimens.
  
  
  RESULTS
  Ultrasonography showed an enlarged hypoechoic pancreas with sausage-like appearance and no lobulation in the contour of the pancreas. On computed tomography imaging, delayed enhancement of the swollen pancreatic parenchyma became evident. Dense lymphoplasmacytic infiltration with fibrosis involving peripancreatic tissue was observed throughout almost the entire pancreas. Periductal non-occlusive fibrosis with lymphoplasmacytic infiltration induced narrowing of the pancreatic duct. Stenosis of the common bile duct is frequently associated with autoimmune pancreatitis and is induced by diffuse thickening of the duct wall by the same inflammatory process as that of the pancreas. The fibroinflammatory process also involves blood vessels.
  
  
  CONCLUSIONS
  Characteristic radiological findings of autoimmune pancreatitis are induced with systemic histological changes of lymphoplasmacytic infiltration with fibrosis, and differ from schirrous invasion of pancreatic carcinoma.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, Tokyo, Japan. kamisawa@cick.jp
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Naoto
authors.initials: N
authors.lastname: Egawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakajima
authors.forename: Kouji
authors.initials: K
authors.lastname: Tsuruta
authors.forename: Atsutake
authors.initials: A
authors.lastname: Okamoto
authors.forename: Noriko
authors.initials: N
authors.lastname: Kamata
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Funata
mesh_terms: D000368:Aged; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D003135:Common Bile Duct / Q000000981:diagnostic imaging / Q000473:pathology; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D010195:Pancreatitis / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed