Anomalous systemic arterial supply to the basal segment of the left lung with large vessel giant cell arteritis demonstrated by 18F-FDG PET/CT

We report a rare case of anomalous systemic arterial supply to the basal segment of the left lung (ABLL) coexisting with large-vessel giant cell arteritis (LV-GCA) in a 73-year-old woman. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) demonstrated inflammatory involvement of both the aorta and the anomalous artery. To reduce vascular and perioperative risks, immunosuppressive therapy was initiated first, resulting in improvement in clinical and radiological findings. This case highlights the importance of controlling active vasculitis before definitive surgical treatment.