Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with the prior radiograph , there is a persistent veil - like opacity over the left hemithorax , with a crescent of air surrounding the aortic arch , in keeping with continued left upper lobe collapse . Left hilum and mediastinum are enlarged , as seen on the prior study , compatible with patient 's known mass with hilar and mediastinal adenopathy . There is a trace left pleural effusion . Right lung is clear without pneumothorax . Marked scoliosis the thoracic spine is again seen .
    OUTPUT:
    
Persistent left upper lobe collapse , with a similar appearing large left hilar mass and trace left pleural effusion . No pneumothorax identified .