Are bile duct lesions of primary biliary cirrhosis distinguishable from those of autoimmune hepatitis and chronic viral hepatitis? Interobserver histological agreement on trimmed bile ducts.

Background: Primary biliary cirrhosis (PBC) is histopathologically characterized by chronic nonsuppurative destructive cholangitis and ductopenia of interlobular bile ducts. Bile duct injury is also often encountered in chronic viral hepatitis (CVH) and in autoimmune hepatitis (AIH).

Methods: In this study, we performed interobserver agreement analysis on 90 injured bile ducts from liver specimens of PBC (17 cases), CVH (26 cases), and AIH (18 cases), with 30 bile ducts chosen from each disease group. Digital images of bile ducts with minimal periductal elements were recorded in CD-ROM format and sent to 14 observers (six special hepatopathologists, four local hepatopathologists, and four general pathologists). We analyzed the following issues: (1) diagnostic accuracy of PBC, based only on bile duct lesions; (2) classification of bile duct lesions in AIH cases as destructive cholangitis equivalent to PBC-associated injury, or not.

Results: The diagnostic accuracy of PBC cases with severe bile duct injuries was very high (over 80%), although the accuracy in cases with only mild bile duct injuries was low (50% or less). For AIH, each observer classified 9 of the 30 bile ducts, on average, as destructive cholangitis.

Conclusions: This study revealed that 66.9% of PBC cases could be diagnosed based on trimmed bile ducts alone. Bile duct injury similar to that in PBC could be encountered in AIH.