hemosiderin

thumb|Histopathology of a case of chronic pulmonary congestion, showing interstitium with hemosiderin deposition (black arrow), edema and collagenous thickening. The alveolus contains a siderophage (white arrow, characterized by coarse brown pigment, which is slightly refractile). thumb|Hemosiderin image of a kidney viewed under a microscope. The brown areas represent hemosiderin

Hemosiderin or haemosiderin is an iron-storage complex that is composed of partially digested ferritin and lysosomes. The breakdown of heme gives rise to biliverdin and iron. The body then traps the released iron and stores it as hemosiderin in tissues. Hemosiderin is also generated from the abnormal metabolic pathway of ferritin.