Extrapleural hematoma as a complication following thoracic surgery is rare. We report a case of an extrapleural hematoma following pleural lobectomy that resolved completely with nonsurgical treatment. A 63-year-old woman underwent left lower lobectomy for lung cancer through a left posterolateral thoracotomy. She had been prescribed the anticoagulant cilostazol to increase her heart rate for atrioventricular dissociation. Preoperatively, it was stopped, and a temporary pacemaker was placed to counteract bradycardia via the right jugular vein without complication. The chest tube was removed, and cilostazol was resumed on the third postoperative day. On day 7, she suddenly experienced left shoulder pain followed by hypotension, tachycardia, and anemia. Enhanced computed tomography (CT) revealed an extrapleural hematoma rather than a hemothorax. She became symptomatic after rapid infusion. The hematoma resolved without an invasive intervention. The CT results 189 days after the onset showed almost complete regression of the hematoma.