Macrophages are cells mobilized to digest lipids, the main constituent of myelin sheaths, as a result of tissue damage from various causes. They are generally derived from serum monocytes. Englobed lipids have been found within cells by lipid staining and are therefore also called lipid phagocytes or fat granule cells. In contrast, when hemorrhage-induced tissue deposits of iron components such as hemosiderin are englobed, they are referred to as hemosiderin-laden macrophages or iron granule cells.
