Overlooked diagnosis of infected paratracheal air cysts in patients with respiratory symptoms

Rationale: Infected paratracheal air cysts as the focus of respiratory symptoms can be overlooked in practice because of nonspecific symptoms and physician's scant knowledge for this entity. We report 2 cases of infected paratracheal air cyst diagnosed at chest computed tomography (CT) and bronchoscopy/endobronchial ultrasound. Patient concern: Two patients visited our hospital with respiratory symptoms, including cough, sputum, and fever. Diagnoses: Chest CT showed paratracheal cystic lesions with air-fluid level in the thoracic inlet. In the first patient, endobronchial ultrasound revealed a right paratracheal hypoechoic mass corresponding to the lesion on CT scan. In the second patient, bronchoscopy revealed purulent discharge from a dimpling at posterolateral wall of trachea, which was the opening of communication between the trachea and infected paratracheal air cyst. Interventions: Both patients received antibiotic treatment. Outcome: After medical treatment, the patients’ symptoms were improved. Follow-up chest CT scans showed air-filled paratracheal air cysts without internal fluid or rim enhancement. Lessons: A physician should pay attention to paratracheal air cyst in patients with respiratory symptoms when their lungs are clear on CT scan.