Abstract
A 30-year-old man was transported to our hospital with a diagnosis of iatrogenic hemopneumothorax after chest drainage. His chest X-ray showed massive right pleural fluid collection. Chest drainage revealed ongoing massive bleeding. Therefore, an emergency operation was carried out under a diagnosis of intercostal artery laceration or spontaneous hemopneumothorax. The bleeding point was a ruptured vessel between the parietal pleura and bulla at the apex of the lung. After improvement of complicating postoperative re-expansive pulmonary edema, the patient was discharged on the 7th postoperative day. Careful observation after chest drainage is necessary for early diagnosis and treatment of spontaneous hemopneumothorax.