epiphrenic esophageal diverticulum

Clinically, diverticula occurring within the distal 10 cm of the intrathoracic esophagus are termed epiphrenic esophageal diverticula. The majority of epiphrenic diverticula are pulsion-type diverticula, formed by protrusion or herniation through a weak point or defect in the esophageal mucosal smooth muscle layer. Epiphrenic esophageal diverticula are far less common than Zenker's diverticulum. They develop gradually from small to large and are often associated with esophageal dysmotility. Moreover, almost all patients have concurrent hiatal hernia and gastroesophageal reflux. Therefore, it is considered an acquired disease, although congenital factors may also be involved.