Cases

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Extramedullary hematopoiesis in beta thalassemia: As seen on the posteroanterior (Image A) and lateral (Image B) chest radiographs, the patient has multiple, large posterior mediastinal masses. Splenomegaly is present on the abdominal CT scout image (Image C). Cholecystectomy clips are also present. On the first chest CT scan (Image D), the posterior mediastinal masses have soft tissue attenuation but do not involve the neural foramina. On the second CT scan (Image E), the vertebral body and ribs are sclerotic, with coarse trabeculae.

Osseous sclerosis and splenomegaly can be seen in combination in several entities (eg, mastocytosis, myelofibrosis). Hemolytic anemias such as thalassemia or sickle cell disease often lead to cholelithiasis, requiring cholecystectomy at a young age. The differential diagnosis for posterior mediastinal masses includes neurogenic tumors, lymphoma, hematoma, and abscess. Assembling all the above findings leads to the diagnosis of extramedullary hematopoiesis in the setting of thalassemia. Extramedullary hematopoiesis occurs in response to states of deficient bone marrow productivity, such as anemia, myelofibrosis, and leukemia. The reticuloendothelial system (spleen, liver, and lymph nodes) is usually involved in extramedullary hematopoiesis, but the posterior mediastinum, skull, and kidneys can also be involved.