[A Case of Pancreatic Cancer Associated with Autoimmune Pancreatitis].

A 74-year-old man with IgG4-related cholangitis had been treated with steroids for 1 year. In the outpatient clinic, elevated levels of the tumor marker CA19-9 and serum IgG4 were observed. Abdominal enhanced CT showed a 20mm hypovascular tumor in the pancreatic head. ERCP showed narrowingof the main pancreatic duct in the pancreatic head with slight caudal dilation and stricture of the lower common bile duct. We made a diagnosis of pancreatic cancer, and the patient underwent pancreaticoduodenectomy. Pathological examination of the resected tissue revealed a well-differentiated adenocarcinoma surrounded by autoimmune pancreatitis, characteristic of lymphoplasmacytic sclerosingpancreatitis. He is receiving adjuvant chemotherapy with S-1 in the outpatient clinic.