A 41-year-old woman was admitted to the hospital for obstetric surgery
. A preoperative chest x-ray film showed a mediastinal mass. After exa
minations with echocardiography, computed tomography, and magnetic res
onance imaging, we removed a cyst that was 2.7X3.5 cm in size by thora
coscopic means. The patient left the hospital 3 days after the operati
on.