Langerhans' cell histiocytosis (LCH) is a proliferative histiocytosis disorder. The clinical severity of LCH ranges from fatal disorders to isolated bone lesions. Solitary bone lesion of LCH has a good prognosis. We present a case of a 12-year-old girl who suffered from progressive pain over the right proximal clavicle. Clinical presentations and laboratory data showed suspicion of osteomyelitis, however biopsy result was Langerhans' cell histiocytosis. Solitary bone lesion of LCH could mimic osteomyelitis in radionuclide and radiographic surveys. Although LCH is a rare disorder, it should be kept in mind as a differential diagnosis.