Interobserver variation in the histopathological assessment of nonalcoholic steatohepatitis

Pathological assessment is considered as the gold standard for the diagnosis of nonalcoholic steatohepatitis (NASH). However, there is no agreement of histological features required for the diagnosis of NASH. In the present study, eight experienced hepatopathologists read liver biopsy specimen slides of 21 cases of NASH and suspected NASH independently and were asked to assess histopathological features and render a diagnosis. Interobserver variation among pathologists was evaluated by kappa statistics. Significant, good agreement was present in evaluation of the extent of steatosis and grade of fibrosis. Agreement was moderate concerning the localization of steatosis, localization of fibrosis, and glycogen nuclei. Only slight or poor agreement was seen in evaluation of type of steatosis, ballooning, intralobular necroinflammatory change, portal inflammation, and degree of neutrophilic infiltration. Thus the agreement varied for histological variables. Significant, moderate agreement was seen in the diagnosis of NASH but agreement was poor in the diagnosis of suggestive NASH. The agreement for the diagnosis of NASH was not high as for the individual histological findings that were thought to be the basis of the diagnosis. In conclusion, some histological features in NASH might prove useful for the development of a standardized and reliable pathological diagnosis and scoring system.