組織細胞增生症是一種罕見的疾病，臨床嚴重度從致命到只有單一骨病灶。本病例是一位12歲小女孩覺得右邊鎖骨處疼痛情況與日俱增，後來病灶有腫脹和局部紅熱的情形，懷疑是骨髓炎。核醫骨骼掃描和鎵－67發炎婦描影像和骨髓炎相符合，但是此病灶後來開刀取下病理結果是組織細胞增生症。雖然組織細胞增生症很少見，在鑑別診斷中是需要考慮的。

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.