Abstract
A Case of a foregut cyst of the posterior mediastinum in a 5-year-old boy is reported. The patient was admitted to the hospital because of fever and abdominal pain. Chest x-ray films revealed an egg-shaped tumorous shadow on the left side of the posterior mediastinum. Esophagography visualized a left anterior displacement of lower third of the esophagus. Chest CT revealed a 7.5×5.8cm tumor with a low density center in the left posterior mediastinum adjacent to the pericardium, esophagus, and aorta. With a diagnosis of cyst of the posterior mediastinum, an operation under left thoracotomy was performed. The cyst which adhered to the esophageal wall was freed from the esophagus and excised. The excised tumor was 5×6cm in size, oval in shape, and unilocular, and contained brown serous liquid. Histologically, the cyst wall was not lined with epithelium, and contained one muscle layer. There was no cartilage. We diagnosed the cyst as foregut cyst.
