A 57-year-old man presented with a 2-wk history of painless jaundice and weight loss.He had a large illdefined enhancing mass-like lesion in the uncinate process of the pancreas with stricture of the distal common bile duct.Aspiration cytology of the pancreatic mass demonstrated inflammatory cells without evidence of malignancy.Total serum immunoglobulin G level was slightly elevated,but IgG4 level was normal.After the 2-wk 40 mg prednisolone trial,the patient’s symptoms and bilirubin level improved significantly.A follow-up computed tomography(CT) scan showed a dramatic resolution of the pancreatic lesion.A low dose steroid was continued.After six months he self-discontinued prednisolone for 3 wk,and was presented with jaundice again.A CT scan showed newly developed intrahepatic biliary dilatation and marked concentric wall thickening of the common hepatic duct and the proximal common bile duct without pancreatic aggravation.The patient’ s IgG4 level was elevated to 2.51 g/L.Prednisolone was started again,after which his serum bilirubin level became normal and the thickening of the bile duct was resolved.This case suggests that autoimmune pancreatitis can progress to other organs that are not involved at the initial diagnosis,even with sustained pancreatic remission. A 57-year-old man presented with a 2-wk history of painless jaundice and weight loss. He had a large illdefined enhancing mass-like lesion in the uncinate process of the pancreas with stricture of the distal common bile duct. Aspiration cytology of the pancreatic mass demonstrated inflammatory cells without evidence of malignancy. Total serum immunoglobulin G level was slightly elevated, but IgG4 level was normal. After the 2-wk 40 mg prednisolone trial, the patient’s symptoms and bilirubin level improved significantly. A follow-up computed tomography (CT) scan showed a dramatic resolution of the pancreatic lesion. A low dose steroid was continued. After six months he self-discontinued prednisolone for 3 weeks, and was presented with jaundice again. A CT scan setting newly developed intrahepatic biliary dilatation and marked concentric wall thickening of the common hepatic duct and the proximal common bile duct without pancreatic aggravation. the patient’s IgG4 level was elevated to 2.51 g / L. Prednisol one was started again, after which his serum bilirubin level became normal and the thickening of the bile duct was resolved. This case suggests that autoimmune pancreatitis can progress to other organs that are not involved at the initial diagnosis, even with sustained pancreatic remission.