A case of hemothorax following seat-belt injury with a bulla in the apex of the lung: a subtype of spontaneous hemopneumothorax

We experienced a case of a subtype of spontaneous hemopneumothoraxcaused by external forces associated with a seat-beltinjury. A female aged 39 years sustained a minor collision with an oncoming car while she was driving. Although pneumothoraxwas not detected, hemothoraxand bleeding from the area surrounding the subclavian arterywere observed on contrast-enhanced chest computed tomography (CT). After confirming continuous bleeding into the thoracic cavityafter superselective arterial embolization, we performed emergency open surgery. We found a bulla in the apex of the lung, and the thoracic stump of the bulla was considered the source of bleeding. In this case, the direct cause of hemothoraxwas considered to be the external force associated with the seat-beltinjury. When a bulla in the apex of the lung and continuous bleeding are both observed on CT, spontaneous hemopneumothoraxshould be suspected, necessitating open chest surgeryin cases where pneumothoraxis not observed.