The pathology of nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized form of chronic liver injury. Nonalcoholic steatohepatitis (NASH) is the term applied to the microscopically-defined subset of NAFLD with known progression to cirrhosis and the complications that may be associated, including metabolic imbalances, liver failure and hepatocellular carcinoma. NASH is also being considered as a significant precursor of end-stage liver disease, ''cryptogenic cirrhosis'', in which the histologic features of the initial liver disease can no longer be appreciated. Because of the increasing prevalence and the known significance of this form of liver disease, current investigations are focused on discerning the clinical features of susceptible patients, the histopathologic findings that characterize the entity and serve as markers of progression, pathogenetic mechanisms that result in triglyceride accumulation, liver injury and fibrosis, and ultimately, treatment options.