Steatosis is assessed according to the pattern and the amount of fatty infiltration in hepatic tissue sections. Traditionally, fatty accumulation has been classified morphologically as macrovesicular or microvesicular. Macrovesicular steatosis is characterised by a single, bulky fat vacuole in the hepatocyte that displaces the nucleus to the edge of the cell. Among a variety of dis- orders alcohol abuse, obesity, and diabetes mellitus are the main causes behind this form of lipid accumulation. The underlying pathogenesis is related to an excessive triglyceride accumulation in the liver, mainly due to an increased uptake of fatty acids released from adipose tis- sue and/or an augmented de novo synthesis. Defective hepatic export, secondary to reduced lipoprotein synthe- sis, or impaired b-oxidation of fatty acids further increase hepatic triglyceride content