Nonalcoholic fatty liver disease: histopathological evaluation and interobserver agreement

Abstract

Background: Nonalcoholic fatty liver disease comprises a spectrum of lesions ranging from steatosis to cirrhosis, with nonalcoholic steatohepatitis being the progressive form of the disease. Alcohol intake, viral hepatitis and other liver diseases must be excluded. Liver biopsy is the gold standard for diagnosis of the disease and is the only method able to differentiate nonalcoholic steatohepatitis from simple steatosis, to grade inflammation and to stage fibrosis. Aims: To analyze the histopathological findings and evaluate interobserver agreement in biopsies previously diagnosed as steatosis or steatohepatitis. Methods: Seventy needle biopsies were analyzed according to Brunt et al. (4) , with modifications in the grading and staging components. Clinical data of patients were collected. Interobserver agreement was calculated based on histopathological findings. Results: Mild nonalcoholic steatohepatitis (grade 1) was the most common form. If fibrosis was detected, stage 1 was the most frequent. Interobserver agreement was very good for macrovesicular steatosis (K W = 0,82) and good for lobular inflammation (K W = 0,68) and fibrosis (K W = 0,73). Conclusions: The classification of Brunt et al., with modifications, can be applied to diagnosis not only of nonalcoholic steatohepatitis but also of nonalcoholic fatty liver disease, representing a reliable method for use in the daily practice of pathologists.