Myelodysplasia Presenting as Granulocytic Sarcoma of Mediastinum Causing Superior Vena Cava Syndrome

Granulocytic sarcomas (GS) are extramedullary tumor masses of immature myeloid cells, most frequently associated with hematological disorders including acute myeloid leukemia (AML), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS). Recent interest has centered upon the possible biologic properties that enable theses myeloid cells to adhere to tissues and establish a tumor mass. GS presenting as a mediastinal mass is relatively infrequent, and more uncommon is presentation with the superior vena cava syndrome. We present one such case and review some of the available literature.