[Air-filled cysts of tracheal origin: nosological problems and actual frequency].

Air-filled paratracheal bronchogenic cysts are extremely rare. They are lined by respiratory epithelium. We have operated on 2 patients whose cysts were diagnosed by CT scan: one presenting with bloody sputum and the other with dysphagia. Both patients had a history of neck surgery. Because such cases are rare in the literature, their exact origin, whether tracheocele, diverticulum or other form of air-filled cyst, remains a matter of debate. However, their frequency is probably underestimated because most cause few symptoms and are well tolerated. In a recent radiologic study their prevalence was found to be 2% in patients undergoing CT scan.