Preceding orbital granulocytic sarcoma in an adult patient with acute myelogenous leukemia with t(8;21): a case study and review of the literature.

A 25-year old man with a 30 month history of proptosis and pain of the right eye was referred to Severance Hospital of Yonsei University. Orbital computed tomography (CT) demonstrated a huge mass in the right retrobulbar orbit; an incisional biopsy and orbitotomy were performed for diagnosis and orbital soft tissue decompression. Subsequent histopathology disclosed sheets of mononuclear cells in the orbital mass, and immunohistochemical stains demonstrated positive results for myeloperoxidase and CD43, which supported the diagnosis of granulocytic sarcoma (GS). After his 1-year follow-up, the patient presented with pancytopenia, and an ensuing bone marrow aspiration revealed markedly hypercellular marrow replaced by many large abnormal myeloblasts. The patient was diagnosed with acute myelogenous leukemia with t(8;21) preceded by orbital GS. Orbital GS is primarily a disease of children, and extremely rare in adults. To the best of our knowledge, only four cases of this disease in adults have been reported in the literature. Our case is the first report of preceding orbital GS in an adult patient with a complex karyotype including t(8;21).