We report of a 29-year-old man presented with yellow-red, scaling papules on the skin of scalp, retro-auricular folds, inguinal, axillary, chest and abdomen. The lesions had a poikilodermatious appearance in some areas, such as trunk. The patient also had diabetes insipidus and skull osteolytic lesions. The diagnosis of langerhans cell histiocytosis (LCH) was suggested based on H and E staining...