Abstract: Objective To improve the understanding of Langerhans cell histiocytosis（LCH）. Methods Clinical features of 1 LCH patient were reported,including high fever,bone pain,cough,pleural effusion,multiple liver and spleen occupying lesions.PETCT showed that bones,spleen,mediastinum,hepatic lymph nodes were extensively involved.Right iliac bone biopsy revealed that the tumor cells were histocytes with their cytoplasm red stained and the chromatin structure was loose with visible nucleoli.Immunohistochemistry showed S100 + + +,CD1a + +,and CD68 +,which were classified as a high-risk group with multiple systems involved. Results The clinical symptoms of the patient did not improve after one cycle of CHOP chemotherapy.Her bone pain disappeared and her body temperature became normal after one cycle of ICE chemotherapy.The clinical symptoms disappeared after 6 cycles of ICE chemotherapy.Reexamination showed that the bone marrow and positron emission tomography（PET-CT） returned to normal.The patient was followed up for 8 months during which her symptoms were completely alleviated. Conclusion Biopsy is the golden diagnosis standard for LCH and positive immunohistochemical S100 and CD1a are the pathological characteristic of LCH.PET-CT does contribute to its definite staging,measurement of its size and assessment of its clinical outcome.ICE combined chemotherapy can achieve good clinical outcomes when multiple systems are involved.