Pulmonary Langerhans cell histiocytosis [PLCH] is a rare disease. From the insidious onset and non specific manifestation, it is difficult to diagnose PLCH. A report describes a case of 30 years old female with PLCH. She presented with left sided chest pain and sudden onset of breathlessness of few hours duration.

General examination revealed that the patient had tachypnea, but she was hemodynamically stable. Chest examination showed decreased breath sound on left side. Chest x ray revealed left sided pneumothorax. Oxygen was given to the patient and left sided chest tube was inserted.

HRCT of the chest revealed multiple bilateral pulmonary cysts. The final histopathological diagnosis was pulmonary Langerhans cell histiocytosis X after lung biopsy. Pleurodesis was performed. Follow up for more than 2 years revealed no recurrence