We report the case of a 66-year-old woman with neurofibromatosis type 1 who developed chest wall bleeding with severe scoliosis and a giant intrathoracic meningocele. She was brought to the emergency department with acute-onset of left-sided chest pain and clinical signs of hypovolemia. Bleeding control was difficult in the first operation because the tissue was friable and there were multiple subcutaneous bleeding points. During the first operation, the patient developed disseminated intravascular coagulation, which required immediate management; therefore, the surgery was aborted and a repeat surgery was performed later to stop the bleeding. The major cause of bleeding was presumed to be the mechanical stretching of the intercostal arteries and branches of the internal thoracic artery secondary to the severe deformity of the thoracic vertebra and ribs. The massive bleeding remained as a hematoma and did not lead to development of hemothorax. This was believed to be because the giant intrathoracic meningocele supported the expansion of the hematoma and prevented the perforation of the visceral pleura. After the second operation, the hematoma shrunk gradually; however, the patient required ventilatory support because the decrease in the size of the hematoma was accompanied by the expansion of the meningocele. (c) 2011 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.