Is the Opacity on the Chest X-ray Pathological? “Azygos Lobe”

Chest radiography (chest X-ray) is one of the most frequently used radiological examinations in the pediatric emergency departments (PEDs).It is helpful in the diagnosis of infections, including malignancy, foreign bodies, and bone structure deformities.Chest X-rays should be interpreted in a particular order, and all anatomical structures should be evaluated.Here, three cases in which the opacity detected in the chest X-ray was evaluated as the azygos lobe are presented, and this rare condition is discussed.Three patients were admitted to university hospital's PED and incidentally diagnosed with azygos lobe.Case 1, a 16-year-old male patient, presented with chest pain on the left side of the sternum.Case 2, a 9-year-old male patient, presented with dyspnea.Case 3, a 16-year-old female patient, presented with fever and abdominal pain.The tear-shaped opacity detected on the chest X-ray of all three cases was evaluated to be an azygos lobe.Although many cases of the azygos lobe are described, knowledge of it among clinicians is still insufficient.We presented these three cases to raise awareness of the azygos lobe, and remind physicians that its typical appearance on chest X-ray can be easily recognized.