Emergency surgery for hemothorax due to a ruptured pulmonary arteriovenous malformation.

Pulmonary arteriovenous malformation (PAVM) is a potential cause of hemothorax. The risk of PAVM rupture is reported to be higher during pregnancy for several reasons, including increased body fluid and a change in hormonal conditions. A 34-year-old pregnant woman suddenly felt right chest pain and dyspnea in the 28th week of gestation. Chest X-ray and computed tomography showed massive right pleural effusion. Her vital signs gradually deteriorated with hemorrhagic shock, necessitating emergency surgery. During exploratory thoracoscopy, active bleeding from the middle lobe was noticed and gauze packing was required to maintain her blood pressure. Following conversion to major thoracotomy, wedge resection of the middle lobe was performed with a linear stapler, and finally, her general condition became stable. Her postoperative course was uneventful. A histological examination of the resected specimen confirmed the diagnosis of ruptured PAVM. Her baby was successfully delivered at the 38th week of gestation.