Orbital granulocytic sarcoma in a myelodysplastic syndrome.

PURPOSE. To report an elderly patient with a primary myelodysplastic syndrome (MDS) type refractory anemia with excess of blasts (RAEB) who developed an orbital granulocytic sarcoma (GS) as a harbinger of an acute myelogenous leukemia (AML). METHODS. A 77-year-old man was diagnosed as having a MDS type RAEB. Eight months later he developed a progressive painless proptosis in his left orbit. A computed tomography (CT) scan revealed a large irregular mass involving the orbit. It showed heterogeneous soft tissue density and no osseous cortical destruction was observed. A diagnostic lateral orbitotomy with an excisional biopsy were performed. RESULTS. Histopathology showed sheets of immature granulocytic cells. Immunohistochemical staining was positive for markers for myeloperoxidase, which supported the diagnosis of GS. CONCLUSIONS. Reports of a GS complicating the course of a MDS are few. Sites of detection of the extramedullary tumors (EMT) in MDS vary, although cutaneous sites predominate. An orbital site is a very rare localization of this tumor in adults. The case we report is the first one with an orbital granulocytic sarcoma in an MDS-type RAEB in an elderly patient.