[Pathological examination for liver transplantation]

Abstract

Liver biopsy plays an important role in the histopathological evaluation of the transplanted liver. In this review, we would like to describe the histological features of various forms of diseases such as allograft rejections occurring in transplanted livers. When severe steatosis is found in the donor liver, transplantation is contraindicated. Ischemic liver damage caused by transplant hypoperfusion is called harvesting or re-perfusion injury and characterized by the histological features of liver-cell ballooning, centrilobular cholestasis, and apoptosis of hepatocytes. Acute rejection occurring more commonly in the first few weeks after transplantation is defined by the diagnostic triad of portal inflammatory infiltrates, endothelialitis, and bile duct damage, whereas chronic rejection is characterized by the presence of ductopenia and foam cell arteriopathy. Obstruction of the hepatic artery leads to severe centrilobular necrosis of the allograft. Among viral infections affecting the allografts, cytomegalovirus infection occurs most frequently, and typical intranuclear or cytoplasmic inclusions are hallmarks of the infection. Post-transplantation lymphoproliferative disorders are closely associated with Epstein-Barr virus infection. Therapeutic drugs such as azathioprine and cyclosporin A also cause liver damage, but specific histological features of drug-induced injury have not yet been clarified. Recurrence of original diseases such as viral hepatitis or malignant tumors is also evaluated by the liver biopsy.