BackgroundPulmonary lacerations caused by an avulsion force on an adhesion between the lung and chest wall following blunt thoracic injury are very rare. They may result in pneumothorax and/or hemothorax and may not be immediately apparent clinically or radiologically.Case presentationWe present the case of a healthy 34-year-old male who sustained blunt thoracic injury. He was clinically stable, and his initial routine images were unremarkable. The patient was discharged home on the same day. He presented a week later with a massive hemothorax requiring surgical intervention which revealed bleeding from an avulsed adhesion between the lung and chest wall. Bleeding was successfully controlled by hemostatic agent, and the patient had an uneventful recovery.ConclusionHemothorax requiring intervention from an avulsed adhesion may occur following blunt thoracic trauma. Initial imaging and clinical finding may be misleading. Close follow up and adequate patient education should be ensured prior to discharge following seemingly trivial trauma.