Granulocytic sarcoma presenting as an epidural mass with acute paraparesis in an aleukemic patient. Granulocytic sarcomas are rare tumors composed of granulocytic precursor cells. They are most commonly encountered in patients with acute myelogenous leukemias and myeloproliferative disorders in blast crisis. Rarely, patients presenting with granulocytic sarcoma show no evidence of acute leukemia. The authors report an aleukemic patient with acute paraparesis from an epidural granulocytic sarcoma. Only five such cases have been reported previously. Immunoperoxidase stain for lysozyme and chloroacetate esterase stain were used to prove the myeloid origin of the tumor cells. 