RESUMEN
We report the case of a 57-year-old patient admitted for dyspnea and dry cough. Thoracic radiograph showed a right pneumothorax and right paracardiac opacity. Thoracic drainage was carried out allowing the return of the lung at the wall. Chest CT-scan revealed right upper mediastinopulmonary mass taking contrast material associated with a nodular thickening of the pleura. CT-guided biopsy of the mass and the pleural nodules concluded to pulmonary leiomyosarcoma. Death occurred one month after diagnosis confirmation. Pneumothorax is a usual mode of revealing sarcoma's pulmonary metastases; however, it is exceptionally associated with primitive pulmonary sarcomas. Our case is the second published case, to our knowledge, of primitive pulmonary leiomyosarcoma presenting with pneumothorax.