Primary Spontaneous Pneumothorax with an Azygos Lobe

: A-21-year old man presented with dyspnea and a chest radiograph showed a right pneumothorax. Chest computed tomography revealed a collapsed lung and floating membrane, which was the lowermost part as a tear-shaped shadow. After the chest tube was inserted and surgical management was performed using a video-assisted thoracoscopic approach. At surgery, the visceral and parietal layers of pleura forming the mesoazygos were not fused, and azygos vein had a partial mobility. There was no adhesion between an upper lobe and visceral pleura. A stapling bullectomy was performed. The azygos lobe is a common malformation and has a reported incidence of 0.05~0.4% on health screening. The presence of an azygos lobe is usually assumed to be of no significance. We report a case and discuss the problems that it posed for surgical management.