A myeloid sarcoma (MS) is an extramedullary tumor consisting of primitive granulocytic precursor cells. Although most such tumors have been reported in patients with acute myelogenous leukemia, MS is rarely recognized as an isolated tumor without any evidence of leukemia. However, in such cases, the initial diagnosis of MS can be difficult, so initial misdiagnosis rates of up to 75% have been reported. This report describes an unusual case of MS in a 3-year 5-month-old girl presenting as bilateral renal enlargements, and brain masses, with multiple bone involvements, but no hematological abnormalities.