A Case of IgG4-Related Autoimmune Pancreatitis and Retroperitoneal Fibrosis

IgG4-related systemic diseases include autoimmune pancreatitis and a variety of extrapancreatic lesions, including retroperitoneal fibrosis, sclerosing cholangitis, and tubulointerstitial nephritis. This report describes a case of IgG4-related autoimmune pancreatitis and recurrent retroperitoneal fibrosis, from which the patient recovered via steroid therapy. A 70-year-old female presented with abdominal pain and jaundice. She had been treated with prednisolone for recurrent retroperitoneal fibrosis for 3 years. An abdominal computed tomography demonstrated bilateral hydronephrosis caused by retroperitoneal fibrosis, intraand extra-hepatic bile duct dilatation and diffuse pancreas enlargement. Endoscopic Retrograde Cholangio-Pancreatography showed intrapancreatic bile duct stenosis and IgG4 stained cell infiltration was observed on biopsy tissues of the duodenal papilla and retroperitoneum. After 3 months of steroid treatment, bile duct stenosis, pancreas enlargement, and retroperitoneal fibrosis improved. Also, an elevated serum IgG4 level returned to the normal range, and IgG4-positive plasma cells disappeared from the follow-up biopsy tissues of the duodenal papilla.