Seronegative Autoimmune Hepatitis With Primary Biliary Cholangitis Features Presenting As Acute Biliary Disease: A Case Report

Antimitochondrial antibody (AMA) positivity and cholestasis can complicate the distinction between autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC)-AIH overlap.This distinction is particularly difficult during severe acute hepatitis, when cholestasis may accompany hepatocellular injury.A 69-year-old woman presented with progressive abdominal pain and jaundice.Initial magnetic resonance cholangiopancreatography findings were interpreted as cholecystitis and cholangitis.Persistent hyperbilirubinemia despite antibiotic therapy, together with the absence of biliary obstruction on repeat imaging, prompted investigation for a primary hepatic disorder.The initial alanine aminotransferase (ALT) concentration was 1,522 U/L, and serum immunoglobulin G was 23 g/L during the acute illness.AMA was positive, whereas antinuclear and smooth muscle antibodies were negative; viral hepatitis serology was also negative.Liver biopsy demonstrated severe hepatitis with significant interface activity, multifocal bridging necrosis, and focally prominent plasma cells.Associated canalicular and ductular cholestasis was considered secondary to the hepatic process, and no diagnostic histological features of PBC were identified.These findings supported a working diagnosis of AIH with AMA positivity and cholestatic features, with possible PBC-AIH overlap.Prednisolone was introduced, followed by azathioprine for maintenance immunosuppression.During follow-up, jaundice and pruritus resolved, and ALT and bilirubin normalized.Ursodeoxycholic acid (UDCA), initiated during the diagnostic work-up, was withdrawn after biochemical recovery because of suspected intolerance.This case illustrates the value of clinicopathological assessment when acute hepatitis presents with biliary imaging abnormalities.Numerical Paris criteria thresholds supported consideration of overlap, but secondary cholestasis and the absence of diagnostic PBC histology limited certainty.AMA-positive AIH remained a plausible alternative.