<unk>  is a rare benign congenital malformation of the tracheobronchial tree derived from the ventral aspect of the foregut. It most frequently occurs in the middle mediastinum, in the early stages of gestation or in the lungs, at the later stages of gestation. Atypical locations may be explained by its embryologic origin. 
Patients with<unk>  may be asymptomatic or present with respiratory distress, increasing stridor,  feeding difficulties, chest pain, cough, progressive dysphagia, odynophagia, purulent sputum, dyspnea, anorexia and/orweight loss.
Radiologic findings are useful to differentiate<unk> s from other cysts but they may not always confirm the diagnosis. Diagnosis is confirmed by surgical excision, which is curative, and histological findings of ciliated columnar epithelial lining of the cyst.
Bronchogenic cyst
Tracheal diverticulum
Pulmonary cystic lymphangiectasis
Colloid cyst
Peritonsillar abscess
Mediastinal lipomatosis
Bronchopleural fistula
Pulmonary artery sarcoma