Liver transplant biopsy interpretation: Diagnostic considerations and conundrums

Liver transplantation is now a well-established therapeutic strategy for irreversible acute and chronic liver diseases. There is a broad spectrum of complications encountered in early and late period after transplantation and these contribute to significant morbidity and mortality. Distinguishing among these complications often requires interpretation of allograft biopsies. Histology is the gold standard for the diagnosis of rejection. However, interpretation of these biopsies is quite challenging due to the atypical and complex histomorphology. Multiple simultaneous insults, effects of immunosuppression (IMS), de novo complications, and presentations distinct from non-transplant setting are a few cardinal concerns. Awareness of the time period of occurrence of various complications, the most characteristic histological features or patterns, and distinguishing features between various complications are crucial. The management can be completely divergent; hence, recognition of dominant problem and interpretation in appropriate clinical context is much needed. This review focuses on histopathology of major complications accountable for early and late graft dysfunction. Tabulation of clinico-pathological features to distinguish various complications helps to solve the conundrums and arrive at the correct diagnosis.