[Secondary spontaneous pneumothorax due to a ruptured bulla at a left-sided azygoesophageal recess in a patient with right aortic arch].

Significant frequency of ruptured bullae at the azygoesophageal recess (AER) in secondary pneumothorax patients was reported recently. In normal anatomy, the AER usually exists only in the right thorax. We herein report a case of secondary spontaneous pneumothorax due to a ruptured bulla at a leftsided AER-like structure in a patient with right aortic arch. The case was a 70-year-old man who developed left spontaneous pneumothorax secondary to pulmonary emphysema. He was initially treated by thoracic drainage, but in vain, and finally referred to our department because of prolonged air leakage. Preoperative computed tomography demonstrated a bulla formation at a recess between the rightsided descending aorta and thoracic vertebrae. In thoracoscopic surgery, we confirmed air leakage from the bulla at the recess and the bulla was subsequently ligated. To the best of our knowledge bulla formation at a left-sided AER-like structure has never been reported. Local overinflation of the lung parenchyma may have been a cause of bulla formation in this case.