Hemosiderin

Hemosiderin or haemosiderin is an abnormal microscopic pigment found in the human body. Hemosiderin is composed of iron oxide and can accumulate in different organs in various diseases. Iron is required by many of the chemical reactions in the body but is toxic when not properly contained. Thus, many methods of iron storage have developed.

Humans store iron within a protein called ferritin. The form of iron in ferritin is Iron(III) oxide-hydroxide. By complexing with ferritin, the iron is made water soluble. Several diseases result in deposition of Iron(III) oxide-hydroxide in tissues in an insoluble form. These deposits of iron are called hemosiderin. Although these deposits often cause no symptoms, they can lead to organ damage.

Pathophysiology

Hemosiderin often forms after bleeding (hemorrhage).cite web |url=http://library.med.utah.edu/WebPath/FORHTML/FOR138.html |title=Forensic Pathology |format= |work= |accessdate=] When blood leaves a ruptured blood vessel, the cell dies and the hemoglobin of the red blood cells is released into the extracellular space. White blood cells called macrophages engulf (phagocytose) the hemoglobin to degrade it, producing hemosiderin and porphyrin.

Diseases associated with hemosiderin deposition

Hemosiderin may deposit in diseases associated with iron overload. These diseases are typically diseases in which chronic blood loss requires frequent blood transfusions, such as sickle cell anemia and thalassemia.

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