Isolated involvement of lungs in the course of Langerhans'-cell histiocytosis (LCH) is very rare in childhood. Spontaneous pneumothorax (PTX) may occur during the course which necessitates rapid intervention. We present a 17 months-old girl who was sent with the pre-diagnosis of miliary tuberculosis. Despite antituberculosis therapy, her pulmonary function deteriorated. The chest tomography showed a different lung pattern which is suggestive of LCH. The biopsy findings and immunohistochemistry staining supported the diagnosis. She experienced recurrent pneumothorax incidences which were managed by drainage. She responded well to chemotherapy. Although rare, isolated pulmonary LCH should be remembered in differential diagnosis of cystic lung disease in childhood. On time diagnosis, appropriate therapy and rapid intervention for pneumothorax have important impacts on patient prognosis.