Massive Bronchogenic Cyst

      A 22-year-old woman presented to the emergency room after fainting on the subway. At presentation, she was awake and alert with normal vital signs. Her medical history was significant for epilepsy treated with Topamax and a small mediastinal cyst seen on computed tomography scan 2 years earlier. She was a current smoker and complained of intermittent palpitations but denied fevers, chills, chest pain, and shortness of breath. Physical examination was unremarkable.
      A chest radiograph demonstrated a large lobulated density above the diaphragm and posterior to the heart (Figure 1). The left ventricle appeared compressed, possibly impairing ventricular function and explaining the patient's syncopal episode. Computed tomography scan demonstrated a large fluid filled mass in the inferior aspect of the middle mediastinum, measuring 21.5 cm × 14.2 cm × 11.4 cm, and extending into bilateral pleural spaces. Mild mass effect with compressive atelectasis on the adjacent lower lobes was identified (Figure 2). The remaining mediastinal, hilar, and cardiac structures were normal, and the remaining lung fields were clear without significant pleural effusions.
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      FIGURE 1Posterior-anterior view from chest radiograph demonstrates large mediastinal mass.
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      FIGURE 2Mediastinal windows from computed tomography scan of chest demonstrating massive middle mediastinal cyst displacing heart anterior and superior in axial (a) and coronal views (b and c).
      The patient underwent elective excision via small right thoracotomy. At resection, a simple cyst without septation was found. It was posterior and inferior to the left atrium, surrounding the inferior vena cava on all sides for a distance 3 to 4 cm. The mass extended into the left chest beyond the descending aorta and contained approximately 1500 ml of clear straw-colored fluid. The cyst was carefully dissected free of its mediastinal and pleural attachments, taking care not to leave any residual cyst wall in place. The pathologic diagnosis confirmed the mass to be a simple bronchial cyst with ciliated epithelial lining.
      Postoperatively, the patient had prolonged chest tube drainage, but the course was otherwise unremarkable. She was discharged on postoperative day 7. At follow-up, she was without complaint and returned to normal activity.