Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Re - demonstrated is a left perihilar opacity extending to the left retrocardiac region likely representing developing pneumonia , slightly progressed since yesterday . The cardiomediastinal silhouette is normal . There is no pleural effusion and no pneumothorax .
    OUTPUT:
    
Slightly worsening left perihilar and retrocardiac opacity likely representing developing / worsening pneumonia .