Hidden lung findings in 10,000 patients presenting to anesthesia outpatient clinics for preoperative evaluation: Azygos Lobe

The azygos lobe is usually considered to be a continuation of the upper lobe of the right lung. The azygos vein passes over the right main bronchus and is characterized by its distinct passage. This variation is not typically considered part of the normal anatomy of the right lung and can result in various clinical conditions. The prevalence of the azygos lobe varies among different populations, but it is generally reported to be between 0.1% and 1%. From an anatomical perspective, the azygos lobe, formed by the separate continuation of the right upper lobe bronchus, is an important structure to consider in surgery and anesthesia. Diagnosis is usually made using imaging techniques, and the presence of the azygos lobe should be carefully considered when planning and performing endotracheal intubation during induction of anesthesia. In 73 out of 10,000 patients, the presence of the azygos lobe may affect the anatomical structure of the airway during anesthesia management; therefore, ventilation strategies should be adjusted accordingly. Our study aims to determine the prevalence of the azygos lobe in patients attending the anesthesia clinic for preoperative. It also aims to raise awareness of radiologically missed anatomical variants and avoid unnecessary surgical delays and consultations by differentiating the azygos lobe from bullae, masses, or abscesses.