Congenital bronchogenic cysts are usually located in the mediastinum or develop as intrapulmonary cysts. Gross examination of excised bronchogenic cysts shows them to be unilocular; histologically, these lesions are characterized by the presence of respiratory-type pseudostratified epithelium as well as small islands of cartilage and seromucinous glands. We report a case of a mediastinal bronchogenic cyst having pulmonary parenchyma within the cyst wall. The rarity of our case, the pathological and clinical features and the embryological development of bronchogenic cysts are briefly discussed.