Myeloid (granulocytic) sarcoma of epididymis as rare manifestation of recurrent acute myelogenous leukemia.

Myeloid sarcoma involving the genitourinary system is a rare complication associated with acute myelogenous leukemia or other myeloproliferative disorders. The diagnosis is made by pathologic findings of diffuse infiltration of intermediate-size neoplastic cells and fibrosis of the affected organ. Immunohistochemically, the cells stain positive for myeloperoxidase, CD45, and CD117 but negative for CD34. Treatment involves local surgical extirpation, radiotherapy, and chemotherapy. We report the second known case of myeloid sarcoma involving the epididymis in a patient with a history of acute myelogenous leukemia.