Primary biliary cirrhosis with multinucleated hepatocellular giant cells: implications for pathogenesis of primary biliary cirrhosis.

Histological and clinical features of syncytial giant cell hepatitis (GCH) are rarely observed in adults, and the disease has been associated with several autoimmune disorders and drug reactions. We describe here the case of a 62-year-old woman who presented with evidence of severe acute hepatocellular injury and cholestasis. Serum work-up demonstrated antimitochondrial antibodies specific for primary biliary cirrhosis (PBC) autoantigens, whereas markers of viral infection including hepatitis viruses, paramyxovirus and measles virus were negative. Liver histology revealed the presence of multinucleated hepatocellular giant cells in the parenchymal areas surrounding bridging necrosis. Importantly, damaged interlobular bile ducts were also observed within the lymphocyte-infiltrated portal tracts. Further study using transmission electron microscopy demonstrated the presence of filamentous strands and particles resembling paramyxovirus nucleocapsids in the cytoplasm of syncytial giant cells. To our knowledge, this is the first case of PBC with histological and clinical evidence of syncytial GCH in an adult, and we submit that it might provide novel clues in the enigma of PBC pathogenesis.