We report the case of a patient with intrathoracic extramedullary hema
topoiesis presenting as a posterior mediastinal tumor in response to c
hronic hemolytic anemia. Noninvasive studies including chest roentgeno
grams, computed tomographic scans, magnetic resonance images, and nucl
ear scans can establish the diagnosis in most cases. In equivocal case
s, transthoracic needle biopsy and open biopsy should be considered. S
urgical resection is recommended only for patients with symptoms of co
mpression.