Abstract： [Objective] A case of 34-year-old male was admitted for persistant painful skin ulcer in both axillary regions for 1 year as well as oppression in the chest,fatigue and polyuria for 3 years.He also suffered from diabetes insipidus and exophthalmos.Skin examination showed infiltrated nodules and ulcerated plaques mainly located in the subaxillary and genital regions,as well as widespread skin rashes,scaly or crusted papules.Histopathology revealed a diffuse infiltrate of Langerhans's cells throughout the entire dermis.The tumor cells were positive for CD1a and S-100.Finally,a diagnosis of Hand-Schüller-Christian disease was made based on the histopathological and immunohistochemical findings.At present,no specific treatment is available for Hand-Schüller-Christian disease.Generally speaking,combined chemotherapy is recommended for Hand-Schüller-Christian disease with multisystemic involvement,and surgical operation or radiotherapy for unifocal lesions.