Fatty liver disease (FLD), also known as hepatic steatosis, is a condition where excess fat builds up in the liver. Often there are no or few symptoms.Occasionally there may be tiredness or pain in the upper right side of the abdomen. Complications may include cirrhosis, liver cancer, and esophageal varices.There are two types of fatty liver disease non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease. NAFLD is made up of simple fatty liver and non-alcoholic steatohepatitis (NASH). The primary risks include alcohol, type 2 diabetes, and obesity
Fatty change represents the intracytoplasmatic accumulation of triglycerides (neutral fats). At the beginning, the hepatocytes present small fat vacuoles (liposomes) around the nucleus (microvesicular fatty change). In this stage, liver cells are filled with multiple fat droplets that do not displace the centrally located nucleus. In the late stages, the size of the vacuoles increases, pushing the nucleus to the periphery of the cell, giving characteristic signet ring appearance (macrovesicular fatty change).
These vesicles are well-delineated and optically “empty” because fats dissolve during tissue processing. Large vacuoles may coalesce and produce fatty cysts, which are irreversible lesions. Macrovesicular steatosis is the most common form and is typically associated with alcohol, diabetes, obesity, and corticosteroids. Acute fatty liver of pregnancy and Reye’s syndrome are examples of severe liver disease caused by microvesicular fatty change.
Severe fatty liver is sometimes accompanied by inflammation, a situation referred to as steatohepatitis. Progression to alcoholic steatohepatitis (ASH) or non-alcoholic steatohepatitis (NASH) depends on the persistence or severity of the inciting cause. Pathological lesions in both conditions are similar. However, the extent of inflammatory response varies widely and does not always correlate with degree of fat accumulation.