Unilateral Thoracic Opacification With Volume Loss

Abstract

Pulmonary agenesis is a rare congenital thoracic disorder that affects approximately one in 10,000 individuals and shows no gender preference. This disorder is characterized by complete absence of the bronchi and vessels, and pulmonary parenchyma; pulmonary aplasia may show a small rudimentary bronchus unaccompanied by vessels or alveoli. Many patients with pulmonary agenesis or aplasia die in infancy of respiratory infections, respiratory insufficiency, or associated congenital disorders. The thoracic imaging appearance of pulmonary agenesis or aplasia consists of complete opacification of one hemithorax with severe volume loss evidenced by extensive shift of the cardiomediastinal structures toward the affected side. The imaging appearance of pulmonary agenesis or aplasia must be distinguished from a number of other conditions characterized by extensive pulmonary parenchymal volume loss such as pulmonary hypoplasia, mainstem bronchial obstruction with complete collapse of one lung, extensive fibrothorax, and pneumonectomy. The complete absence of lung tissue and a pulmonary artery on the affected side confirms the diagnosis and may be best appreciated on thoracic computed tomography.