BackgroundSpontaneous hemopneumothorax is a rare condition that can be life-threatening if not promptly diagnosed and treated. We report a case of early treatment with transcatheter arterial embolization and video-assisted thoracoscopic surgery.Case presentationA 19-year-old Japanese male was diagnosed with left pneumothorax and underwent chest tube drainage. A total of 10 hours after admission, the patient developed dyspnea, chest pain, and sudden massive bloody effusion. Contrast-enhanced computed tomography revealed contrast extravasation near the left lung apex, and spontaneous hemopneumothorax was diagnosed. Angiography revealed bleeding from a branch of the subscapular artery and transcatheter arterial embolization was performed. The patient underwent video-assisted thoracoscopic surgery and recovered uneventfully.ConclusionsAnesthesiologists involved in urgent surgeries must be aware that a patient with spontaneous pneumothorax can develop a hemopneumothorax, even when full lung expansion has been obtained following chest tube drainage, owing to latent aberrant artery disruption. Interprofessional team engagement is essential for spontaneous hemopneumothorax management.