S2735 Overlap Syndrome: A Case of Autoimmune Hepatitis Vs Primary Biliary Cholangitis

Introduction: Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are immune-mediated liver diseases that can be seen commonly as separate entities, and uncommonly seen together as an overlap syndrome. They are often differentiated based on clinical presentation, serological, imaging and histological parameters. Early recognition of overlap syndrome is very important, as it can significantly change the course of management. Here we report a case of a 47-year-old male that was subsequently diagnosed with the uncommon entity of overlap syndrome. Case Description/Methods: A 47 year male with no prior medical history presented with diffuse pruritus for 2 months that worsen with hot showers, dizziness, unintentional weight loss of 35 pounds over 3 months period without changes in appetite, foamy dark urine without dysuria or hematuria. On presentation, hemodynamically stable. His physical exam was notable for mild abdominal tenderness in the hypogastric region and the liver palpable 1 inch below costal margin. No scleral icterus, spider angioma or asterixis was noted. Laboratory and autoimmune analysis is shown in figure C. A liver biopsy showed expanded portal tracts by periportal fibrosis, marked ductular reaction, and lymphoplasmacellular infiltration with eosinophils, which can be appreciated in figures A and B. There was granulomatous reaction in the portal tracts, bile duct loss and mild lobular necroinflammation. There was also canalicular cholestasis, focal hyperplasia of hepatocytes and glycogenated nuclei. One medium sized bile duct with periductal fibrosis. Based on these findings the diagnosis of AIH-PBC overlap syndrome was made. The patient was subsequently started on ursodiol and prednisone with significant improvement in liver enzymes and bilirubin. Discussion: AIH-PBC is the most common form affecting roughly 10% of patients with AIH or PBC. Our patient has met the diagnostic criteria for both AIH and PBC. Overlap in clinical features, laboratory tests, histological and imaging can be appreciated and often difficult to distinguish. Many patients that are diagnosed with overlap syndrome require additional treatment, compared to solely AIH or PBC, thus it is imperative to not delay or miss the diagnosis as it can worsen outcomes.Figure 1.: Figure A: Lymphoplasmacellular infiltrate with eosinophils. Figure B: Periportal Fibrosis.Table 1.: Figure C: Laboratory analysis and Autoimmune work up.