Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Since the prior PET - CT exam , the right pleural effusion has increased in size , with known right lower lobe mass obscured . The there is a small left pleural effusion seen . The mild ground - glass opacity in the left lower lung is potentially concerning for pneumonia versus atelectasis . No pneumothorax . Heart size difficult to assess . Bony structures appear grossly intact .
    OUTPUT:
    
Interval development of a right pleural effusion , moderate in size . Small left pleural effusion with left basal ground - glass opacity concerning for atelectasis versus pneumonia .