ObjectiveTo investigate the clinical features of Pulmonary Langerhans' cells histiocytosis (PLCH). MethodsFour cases of PLCH diagnosed by histopathologic examination between August 2004 and September 2013 were retrospectively analyzed. ResultsFour male patients aged from 19 to 46 year old, including three smokers. The main symptoms were chest tightness, cough, and dyspnea. Pneumothorax was presented in two cases, and tuberculosis was in one. The chest high resolution CT (HRCT) revealed lung cysts, nodles, and reticular changes predominantly in the upper and middle lung fields. The pathological Langerhans' cells infiltration were found in the histological biopsy of lesions of the 4 cases. All of the patients were positive in the immuno-histological staining for the S-100 and CD1a antigens. Two cases were positive in Langrin staining (other two patients didn't underwent the staining). Two of the 4 patients were given oral steroid, and the symptoms were improved in one of them. The case with pulmonary tuberculosis improved in symptoms and CT results showed the absorption of the lesion after anti-tuberculosis therapy. Three cases were not followed up. ConclusionPLCH patients were mainly young adults, often presented with chest tightness, cough, and dyspnea. The clinical features of chest HRCT are bilateral cysts, nodules and reticular changes. The disease may be defined by the finding of pathologic Langerhans' cells or the positive staining for CD1a antigens or Langerin.