Unilateral pulmonary agenesis presenting as an airway lesion

Otolaryngologists are frequently consulted to perform rigid bronchosopy in children with suspected foreign body aspiration, mucous plug occlusion of a mainstem or lobar bronchus, or other bronchial mass lesions. Chest radiogr aphs that demonstrate unilateral lung or lobar collapse with a shift of med iastinal structures toward the affected side often prompt this referral. We describe 2 children, one with unilateral pulmonary agenesis and one with p ulmonary aplasia, who presented with these radiologic findings. In each cas e, the definitive diagnosis was made at the time of bronchosopy. The diagno sis might have been suspected preoperatively if the chest radiographs had b een reviewed with this clinical entity in mind. Because of its variable cli nical presentation, diagnosis requires a high index of suspicion. Although computed tomography of the chest is diagnostic, the diagnosis may be sugges ted by chronic changes in the contralateral aspect of the chest wall and lu ng expansion on chest radiographs. Misdiagnosis may subject the patient to the unnecessary risks of bronchoscopy and to potential perforation of the r udimentary bronchus. Although pulmonary agenesis is a rare entity, it may m imic more common airway lesions. Therefore, unilateral pulmonary agenesis s hould be considered in the differential diagnosis of pediatric airway lesio ns.