A 12-year-old boy admitted to a local hospital with fever, migratory arthralgia, and periosteal reaction on X Ray. He was transferred to our hospital because magnetic resonance imaging scan of his whole body showed multiple abnormal signals in bones. Laboratory findings on admission showed the increased erythrocyte sedimentation rate, uric acid, lactate dehydrogenase, alkaline phosphatase, C-reactive protein, immunoglobulin G, hemolytic complement activity and soluble interleukin-2 receptor. Peripheral blood and bone marrow examination did not show any abnormality. The clinical appearance of his condition suggested the diagnosis of chronic recurrent multifocal osteomyelitis (CRMO). He was treated with steroid, however his fever and bone pain continued. A bone and bone marrow biopsy was performed and the results of histopathology showed precursor-B acute leukemia/lymphoma. His bone pain relapsed after the chemotherapy for ALL. Finally, blast cells resembling L3 morphology were detected in the peripheral blood. The reevaluated bone marrow was predominantly replaced with Burkitt like lymphoblasts. He was diagnosed with Burkitt lymphoma by further specific examination.