Successful thoracoscopic resection of costal osteochondroma causing pneumothorax

Costal osteochondromas are rare and infrequently cause pneumothorax and/or hemothorax by injuring the intrathoracic structures. A 13-year-old boy presented with chest pain and dyspnea. Chest radiography revealed a left pneumothorax. Computed tomography revealed a bony and pedunculated mass arising from the fifth rib, pointing directly inward into the thoracic cavity. We suspected that the mass was a costal osteochondroma that had caused a pneumothorax by injuring the left upper lobe of the lungs. The patient underwent a thoracoscopic surgery. A costal osteochondroma arising from the fifth rib and a wound in the left lingular segment were found. We performed wedge resection of the left lingular segment and removed the osteochondroma. Histological examination revealed an osteochondroma with complete resection of the cartilage cap. The patient was discharged on postoperative day 4. We conducted postoperative observations and found no recurrence of the osteochondroma or pneumothorax.