Unilateral absent lung ventilation and perfusion due to a hilar mass

A 54 year old man was referred to us from his private physician for ventilation-perfusion lung scan. In both scans radiotracer activity was absent in the region of the right lung, while a prior chest X-rays film revealed no remarkable abnormality. Subsequent chest computed tomography revealed a hilar mass compressing the hilar vascular and bronchial area components. This case emphasizes that a hilar mass could induce both bronchial and vascular compression with end result matched ventilation-perfusion defect in the entire lung. The chest X-rays film was normal and the chest computed tomography showed a large hilar mediastinal mass. The differential diagnosis of this case is presented.