Granulocytic Sarcoma of the Male Breast in Acute Myeloblastic Leukemia with Concurrent Deletion of 5q and Trisomy 8

We describe a unique case of Granulocytic Sarcoma (GS) in a male, who presented to us with a painless right breast mass without any prior history of Leukemia. GS is an extramedullary tumor of myeloproliferative precursors and may involve multiple sites of the body, but involvement of male breast is extremely rare. In the absence of clinical history or hematological abnormality, GS may be misdiagnosed, depending on the degree of myeloid differentiation present within the tumor. Often it is misdiagnosed as lymphoma. Diagnosis is made by finding eosinophilic myelocytes, myeloperoxidase, chloroacetate esterase staining, and lysozyme immunostain. Chemotherapy regimens similar to acute myeloid leukemia are recommended to treat GS. Recognition of this rare entity is important because early, aggressive chemotherapy can induce regression of the tumor and improve patient longevity.