Isolated Intracranial Myeloid Sarcoma Occurring as Relapse in Acute Myeloid Leukemia.

Myeloid sarcoma (MS) or chloroma is a rare extramedullary tumor composed of extramedullary proliferation of blasts of granulocytic, monocytic, erythroid, or megakaryocytic lineage occurring at sites outside the bone marrow. MS occurs in 2%-8% of patients with acute myeloid leukemia (AML), sometimes it occurs as the presenting manifestation of relapse in a patient in remission. We describe the case of a young male with AML in remission for 6 years presenting with central nervous system symptoms. Magnetic resonance imaging showed an extra-axial altered intensity lesion in the parasagittal parietal region, infiltrating anterosuperiorly into anterior falx, and posterosuperior aspect of the superior sagittal sinus. A biopsy from the lesion was diagnostic of MS which was positive for myeloperoxidase. He did not have any other sites of disease. He has received chemotherapy with FLAG (Fludarabine, Cytosine arabinoside) followed by cranial irradiation and is in complete remission.