The authors report the case of a 61-year old woman who was operated upon for a paraoesophageal cyst of the bronchogenic type. Having reviewed the French literature on the latest cases, they underline the scarcity of these congenital formations which present as mediastinal cystic tumours with benign expression and course. Computed tomography suggests the diagnosis and reveals the intraparietal site of the cyst. A return to the histogenesis of these cysts makes it possible to understand the nosological distinction with the true bronchogenic cysts and to evaluate the recent classifications.