The fine structure of granulocytic sarcoma

Granulocytic sarcoma, a rare manifestation of leukemia, can present as solid and invasive tumors in the central nervous system. We report electron microscopic findings in two such cases of granulocytic sarcoma in this communication. The first case is a granulocytic sarcoma involving mainly the left frontal dura with invasion of the underlying leptomeninges and brain. This was the initial presentation of acute myelogenous leukemia that became apparent seven months later. The second case is a granulocytic sarcoma involving the cervical spine and epidural soft tissue in a known case of chronic myelogenous leukemia. Electron microscopic studies confirm the presence of immature granulocytic cells with specific granules which distinguish these cases from other tumors such as a malignant lymphoma. Granulocytic sarcoma should be considered in the differential diagnosis of neurosurgical cases which present clinically as acute intracranial dural or spinal epidural tumors.