Autoimmune Pancreatitis Accompanied by Cholecystitis, Periaortitis and Pseudotumors of the Liver

A variety of extrapancreatic lesions have been associated with autoimmune pancreatitis (AIP), and these lesions can be difficult to diagnose. We report a patient referred to Shizuoka Cancer Center with the diagnosis of a possible biliary carcinoma with liver metastasis who was shown to have AIP accompanied by pseudotumors of liver. Clinical imaging revealed diffuse enlargement of the head of the pancreas with irregular narrowing of the main pancreatic duct and inferior common bile duct, multiple liver masses, mediastinal lymphadenopathy, and thickening of the wall of the gallbladder and abdominal aorta. Cytology and biopsy from the pancreaticobiliary tract was negative for malignancy. Serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19-9) levels were in the normal range, but soluble interleukin 2 receptor (sIL2R), IgG4 and antinuclear antibody were abnormally high (sIL2R: 2,550 U/ml; IgG4: 764 mg/dl). Corticosteroid therapy was effective and these abnormal findings all improved. This case demonstrates the clinical importance of AIP accompanied by other systemic disorders in the differential diagnosis of patients with a pancreatic mass lesion.