Histology
Histologically, steatosis is physically apparent as lipid within membrane bound liposomes of parenchymal cells. When this tissue is fixed and stained to be better viewed under a microscope, the lipid is usually dissolved by the solvents used to prepare the sample. As such, samples prepared this way will appear to have empty holes within the cells where the lipid has been cleared. Special lipid stains, such as Sudan stains and osmium tetroxide are able to retain and show up lipid droplets, hence more conclusively indicating the presence of lipids. Other intracellular accumulations, such as water or glycogen, can also appear as clear vacuoles, therefore it becomes necessary to use stains to better decide what is accumulating.
Grossly, steatosis causes organ enlargement and lightening in colour. This is due to the high lipid content increasing the organ's volume and becoming visible to the unaided eye. In severe cases, the organ may become vastly enlarged, greasy, and yellow in appearance.
Read more about this topic: Steatosis