A three-year-old girl presented with a right-sided limp and mild fever. Laboratory findings were normal, except for an elevated erythrocyte sedimentation rate (ESR) of 30 mm/h and a C-reactive protein (CRP) level of 1.5 mg/dl. Magnetic resonance imaging showed a periosteal reaction in the distal posteromedial femur with contour bulging and extension of the reaction to the adjacent vastus muscles. Under a working diagnosis of acute suppurative osteomyelitis, she was initially treated with antibiotics and anti-inflammatory agents for one week. However, this did not result in resolution of her problems or normalization of the ESR and CRP. Biopsies of periosteum and muscle revealed Burkitt lymphoma expressing Bcl-6(+). In a child, limping can be the first clinical sign of hematogenous malignancy. In a limping child, if the general clinical course does not show improvement, and empirical treatment is ineffective, a comprehensive evaluation is necessary, including biopsies or bone marrow aspiration.