Evaluating and interpreting bile duct changes in liver allograft biopsies

Despite great advances in treatment of liver disease, liver transplant remains the only cure for end stage liver disease and hepatocellular carcinoma. Successful management of immediate and intermediate post-transplant events determines the overall graft outcome, and pathologists play a key role in achieving long-term graft survival. In evaluating liver allograft biopsies, bile duct changes frequently pose diagnostic dilemma as they could occur in association with or the result of various causes of graft dysfunction, but in which accurate classification and interpretation is key to subsequent management. The approach to interpreting these changes share some similarity to the non-transplant liver biopsy interpretation but several additional factors come into play in transplant setting sometimes making interpretation more complex. This review describes bile duct changes occurring in association with various clinical entities in liver allografts, such as acute and chronic rejection, obstruction, small-for-size syndrome, recurrent biliary diseases, and recurrent fibrosing cholestatic hepatitis C, and others, and discusses an approach to interpreting and reporting them.