DISCUSSION: A bronchocele, also called mucoid impaction, is a mucus-filled dilated bronchus surrounded by aerated lung. Congenital bronchial atresia is a rare developmental abnormality resulting from focal interruption of a lobar, segmental, or subsegmental bronchus with associated peripheral mucus impaction (bronchocele) and hyperinflation of the obstructed lung segment. It was first described in 1953 by BH Ramsay in cystic lung disease. Its incidence is unknown. A recent review found only 12 cases over a 20 year period. The etiology of bronchial atresia is unclear. Majority of the cases are diagnosed incidentally in asymptomatic patients. Symptomatic patients can present with dyspnea or cough and may develop recurrent pulmonary infections or pneumothorax. Characteristic CT findings include mucocele, occlusion of the bronchus central to the mucocele, and emphysematous changes peripherally. A blind-ending bronchus is noted on bronchoscopy. Differential diagnoses include AV malformation, bronchial cyst, intralobar sequestration. No treatment is necessary for asymptomatic patients. Surgical excision is offered for patients who develop complications.