A 4-month-old female with a bronchogenic cyst which communicates with the membranous part of the trachea was presented. She had an acute onset of progressive dyspnea and was transferred to our hospital after intubation of a trachreal tube. A cystic legion in the mediastinum was recognized by the CT-scan and the contrast esophagogram. The content of the cyst was strongly suspected as air by CT-scan. Exploring by the right thoracotomy, we resected almost all the part of the cyst adheded to the membranous part of the trachea. The small defect of the trachea formed at surgery was sutured by 5-0 Ticron and was covered with the pleura and the wall of the esophagus. Three months later, she needed intratracheal intubation and respiratory control for a week because of the stricture of the membranous part of the trachea where the cyst adheded. Except this episode she had an uneventful postoperative course.
