Abstract
Congenital cysts are malformations developing from the endoderm and mesoderm of the digestive and respiratory system in the early weeks of gestation. Unilocular or multilocular dysontogenic cysts are most commonly thoracically located adjacent to the trachea and bronchus and the development of an oesophageal duplication cyst in the oesophageal wall is extremely rare. The duplication cyst in the adult is usually asymptomatic and an incidental diagnosis. Potential symptoms include dysphagia and retrosternal pain. Next to endoscopy and computer tomography, endoscopic ultrasonography is mandatory for a distinguished and accurate preoperative evaluation. Transthoracic excision is crucial for definitive diagnosis and inhibition of complications.