Steatosis, also called fatty change, is abnormal retention of fat (lipids) within a cell or organ.[1] Steatosis most often affects the liver ¨C the primary organ of lipid metabolism ¨C where the condition is commonly referred to as fatty liver disease. Steatosis can also occur in other organs, including the kidneys, heart, and muscle.[2] When the term is not further specified (as, for example, in 'cardiac steatosis'), it is assumed to refer to the liver.[3]

Reference
Wiki: Steatosis