Figure 1. Histopathological changes attributable to biliary tract obstruction and/or stricturing in the liver allograft recipient are identical to those seen in the non-allograft livers. There is usually a very mild portal inflammatory infiltrate, which is usually either neutrophilic or eosinophilic predominant. Occasionally, the infiltrate may contain a predominance of mononuclear cells. However, neutrophils are usually detected in the lumen of bile ducts and between the biliary epithelial cells, as shown in this photomicrograph. Note that the biliary epithelial cells usually do not show the same reactive changes as seen in acute liver allograft rejection where there is an increased N:C ratio, nuclear enlargement and mitotic figures. Note also the presence of mild portal edema.