Large left lung mass: an unexpected finding

An 83-year-old female with a history of two coronary artery bypass graft surgeries and multiple comorbidities presented with aggravation of chronic heart failure accompanied by central cyanosis and nail clubbing. Pulse oximetry was 80-85% on room air, 95% on supplemental oxygen. Chest X-ray showed a large mass in the posterobasal area of the left lung (Panel A, arrow). Common states such as pneumonia or lung cancer were initially suspected, yet, surprisingly, contrast-enhanced computed tomography revealed a giant, 52 mm pulmonary arteriovenous fistula (Panel B, Panel E, #). The structure derived from the segmental branch of the left pulmonary artery (Panel B, ...