Due to pandemic of over-nutrition and its related metabolic risks including central obesity, glucose intolerance, dyslipidaemia and hypertension, non-alcoholic fatty liver disease (NAFLD) becomes an alarming global public health issue. NAFLD is the most common metabolic liver disease in the world with prevalence of 10-45% in different countries. The prevalence of NAFLD is not significantly different between Western countries, and most Asian countries under the influence of “westernized” sedentary lifestyle. NAFLD leads to substantial morbidity and mortality associated with cirrhosis, hepatocellular carcinoma and cardiovascular disease, and becomes the most rapidly growing indication for liver transplantation. Accurate diagnosis of NAFLD is important to facilitate timely and proper management of patients to minimize morbidity and mortality. NAFLD is composed of a full spectrum of conditions from steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. Different non-invasive tests, based on clinical, laboratory and radiological tests, have been developed to assess the degree of steatosis, steatohepatitis and fibrosis in NAFLD. Although liver biopsy is an invasive procedure associated with uncommon but severe complications and limited by sampling error, it remains the gold standard for evaluating hepatic pathology in patients with NAFLD, and is recommended in patients with NAFLD at highrisk of steatohepatitis and advanced fibrosis [bridging fibrosis and cirrhosis], and concurrent chronic liver disease of other aetiology. Understanding pathological terminologies of NAFLD is not only important for pathologists in daily diagnostic practice but also essential for hepatologists in communication with pathologists and patients. One should keep in mind that steatosis and even steatohepatitis are not only exceptional to NAFLD and alcoholic liver disease (ALD) but also found in viral hepatitis C, drug-induced liver injury (e.g. methotrexate, tamoxifen, steroid), Wilson disease and various metabolic liver diseases. This review article provides a brief overview of fundamental pathological changes of NAFLD and practical tips for general pathologists.

With Regards,
Sara Giselle
Associate Managing Editor
Global  Journal of Digestive Diseases