1354 It's Not Always PSC: An Intriguing Case of IgG-4 Sclerosing Cholangitis

Abstract

INTRODUCTION: IgG4-related disease has a broad spectrum of clinical manifestations, when it involves the biliary tract it is termed as IgG4-associated cholangitis. It is the most frequent extra-pancreatic manifestation of type 1 autoimmune pancreatitis and shares clinical and radiographic features with Primary Sclerosing Cholangitis however differentiation is important. CASE DESCRIPTION/METHODS: 71-year-old female with a known history of recurrent pancreatitis and cholangitis status post laproscopic cholecystectomy presented to the hospital with abdominal pain and obstructive pattern of LFTs. Previous ERCPs had revealed common bile duct stricture and a stent had been placed. Prior CT, ultrasound and MRCP all were consistent with findings of pancreatitis with pancreatic duct dilation along with dilation of the intra-hepatic ducts. Endosonographic imaging of the pancreas demonstrated a markedly abnormal pancreas However CA19-9 was normal. She underwent repeat ERCP with biliary dilatation revealing multiple biliary strictures and underwent stent placement in the common bile duct and right hepatic duct. Cytology did not reveal malignant cells and core liver biopsy showed preserved hepatic architecture with no evidence of fibrosis. Features of autoimmune hepatitis are not identified. She presented in a couple of months with similar abdominal pain and ERCP revealed a new 2 cm hepatic duct stricture which was stented. Due to recurrent strictures in the biliary system with failed response to recurrent endoscopic stenting a multi disciplinary decision was made to repeat liver biopsy which revealed very dense lymphoplasmacytic inflammatory infiltrates, numerous lymphoid follicles and obliterative phelebitis similar to findings noted in type I autoimmune pancreatitis. IgG-4 liver stains performed highlighted multiple positive plasma cells establishing the diagnosis of IgG4-sclerosing cholangitis. She was started on steroids and noted to have improvement in her liver enzymes. DISCUSSION: The differentiation of IgG4-related sclerosing cholangitis from primary sclerosing cholangitis and bile duct carcinoma is often difficult however necessary as the former is steroid responsive where as the latter are not. Serum IgG-4 levels are highly predictive for IgG-RD. Tissue acquisition is absolutely essential for the diagnosis. We present a challenging case where due to non-conclusive histological evidence the diagnosis was delayed and later a portal-based inflammatory nodule was seen which is a characteristic feature of this disease.