- Extramedullary hematopoiesis (EMH) is a response to erythropoiesis failure in bone marrow.
- EMH occurs in hemoglobinopathies, myeloproliferative disorders, or bone marrow infiltration
- EMH occurs most often in the spleen and liver and occasionally in the lymph nodes.
- Less common organs include the pleura, lungs, gastrointestinal tract, breast, skin, brain, kidneys, and adrenal glands.
 Imaging Findings
- Enlargement of the involved organ (i.e. hepatomegaly, splenomegaly).
- Thoracic EMS: Unilateral or bilateral, smooth, sharply delineated, often lobulated paraspinal masses without erosion of the vertebral bodies or ribs.
Patient #1: Extramedullary hematopoiesis in a thalassemia patient
 See Also
 External Links
- Haesun Choi, Cynthia L. David, Ruth L. Katz, and Donald A. Podoloff. Case 69: Extramedullary Hematopoiesis. Radiology 2004 231: 52-56.
- Gumbs, RV, Higginbotham-Ford, EA, Teal, JS, Kletter, GG, Castro, O. Thoracic extramedullary hematopoiesis in sickle-cell disease. Am. J. Roentgenol. 1987 149: 889-893.
- Holden, Christopher, Hennessy, Oliver, Lee, Wai-Kit. Diffuse Mesenteric Extramedullary Hematopoiesis with Ascites: Sonography, CT, and MRI Findings. Am. J. Roentgenol. 2006 186: 507-509.