Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal silhouette is normal . The pleura is unremarkable . The right lung is clear . There is a left perihilar opacification with associated left upper lobe linear atelectasis the could represent pneumonia but given lack of URI symptoms code represent a hilar mass causing obstruction . Recommend chest CT for further evaluation .
    OUTPUT:
    
Left perihilar opacification with associated left upper lobe linear atelectasis that could represent pneumonia or a left hilar obstructive mass .