Distinguishing between recurrent primary sclerosing cholangitis and chronic rejection.

1. Recurrent primary sclerosing cholangitis (PSC) is extremely difficult, if not impossible, to distinguish from other causes of biliary strictures or sclerosing cholangitis in allografts using needle biopsy evaluation alone. Technical problems with biliary reconstruction, long cold ischemic times, non-heart beating donors, ABO blood group incompatibility, antibody-mediated rejection, and small-for-size syndrome in reduced-size or living donor livers can also cause similar manifestations in a peripheral core biopsy. 2. Some difficulties in distinguishing between sclerosing cholangitis and chronic rejection (CR) arise because: a) at risk populations are similar; b) both can cause "cholestatic" elevation of liver injury tests; and c) both can lead to intrahepatic cholestasis and small bile duct loss. 3. Etiopathogenesis and pathology of CR and sclerosing cholangitis have some overlapping features, but show distinct differences that result in significantly different and discriminating pathologic manifestations. 4. Clues in the clinical history, evaluation of serial biopsies, and histopathology can be used to distinguish with confidence between sclerosing cholangitis and CR. 5. Potential discriminating features include liver size and gross appearance, and histopathology findings in the arterial tree, hilar lymph nodes, large and small bile ducts, interface zone, lobular, and perivenular regions.