End-stage nonalcoholic fatty liver disease: evaluation of pathomorphologic features and relationship to cryptogenic cirrhosis from study of explant livers in a living donor liver transplant program.

In a proportion of liver cirrhosis, the etiology continues to remain elusive. It is uncertain whether and to what extent cirrhosis evolving from nonalcoholic fatty liver disease contributes to this group of cryptogenic cirrhosis because the clinicopathologic features of nonalcoholic fatty liver disease cirrhosis are largely unknown. We explored these facets by examining the explant livers and clinical data in living donor liver transplant recipients. Among 103 adult liver transplant recipients with different types of chronic liver disease, 30 had a pre-liver transplant diagnosis of cryptogenic cirrhosis. A final categorization of the native liver disease was attempted in these cases on the basis of detail pathomorphological findings in adequately sampled explant liver correlated with careful review of pre-liver transplant clinical data. Of the 30 cryptogenic cirrhosis cases, 19 (63.3%) finally labeled as nonalcoholic fatty liver disease cirrhosis showed histologic features in several respects different from those reported for the early and established phases of nonalcoholic fatty liver disease. Steatosis was infrequent and focal or even absent, whereas variable grades of Mallory hyaline and inflammation were consistently present. Ductular proliferation and hydropic change of hepatocytes were also frequent. Only 9 (47%) of the 19 cases had nonalcoholic fatty liver disease associated risk factors like diabetes and obesity. It was concluded that appreciation of quantitative and qualitative differences in hepatic morphology between the cirrhotic and the early/established stage of nonalcoholic fatty liver disease will help in making a correct diagnosis of nonalcoholic fatty liver disease cirrhosis in the proper clinical setting. When appropriate criteria are used, nonalcoholic fatty liver disease appears to account for close to two thirds of cases currently labeled as cryptogenic cirrhosis.