Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is persistent abnormal soft tissue density centered at the left hilum , potentially related to previously treated malignancy . Previously seen for infrahilar opacity on the left in ___ has resolved . Biapical scarring is again noted . Elsewhere , the lungs are clear . Cardiac silhouette is within normal limits . No acute osseous abnormalities .
    OUTPUT:
    
Left perihilar opacity which may be related to post treatment changes although underlying tumor would be difficult to exclude . No new region of consolidation or evidence of infection .