Mediastinal gastroenteric cyst in a neonate containing respiratory-type epithelium and pancreatic tissue

Mediastinal gastroenteric cyst is an uncommon congenital malformation and a distinct histopathological entity within the family of foregut duplication cysts. This lesion is mainly encountered in neonates and infants. Histologically, it is characterized by double-layered smooth muscle wall and gastric lining mucosa. We report on a case of a 2-day-old girl, with a posterior mediastinal cystic mass associated with T3–T4 hemivertebrae, presenting with severe respiratory distress. The cyst was multilocular, surgically removed, and histopathologic analysis revealed that it was of gastroenteric type. However, in numerous areas of the lesion, respiratory-type epithelium was observed, as well as pancreatic tissue. After removal of the lesion the patient made an uneventful recovery and shows no signs of long-term pulmonary sequelae. We failed to demonstrate in the available literature the presence of this variable epithelial lining within a single mediastinal foregut cyst. In addition, pancreatic tissue within an intrathoracic enteric cyst has been reported only twice. Pediatr Pulmonol. 2009; 44:1240–1243. © 2009 Wiley-Liss, Inc.