A process in which the body attempts to maintain erythrogenesis in response to an alteration in the normal production of red blood cells.
It is observed in hemoglobinopathies, myeloproliferative disorders, neoplasms involving the bone marrow, and other conditions.
Patients with hemoglobinopathies are more likely to have EMH in paraosseous locations.
Patients with myeloproliferative disorders are more likely to have extraosseous masses.
Sites of EMH include the paraspinal regions of the thorax, liver, and spleen.
Other less common locations, include the adrenal gland, bowel, dura mater, and breast.
Extramedullary hematopoiesis in the abdomen most commonly involves the liver and spleen.
Involvement of the kidneys is rare.
Associated with thalassemia and other disorders of hematopoiesis.
Hematopoietic cell colonies may cause disruption of bone cortex and produce extramedullary hematopoietic masses in chest, pelvic cavities, and can cause similar masses that can effect the spinal cord and blood vessels.