Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Retrocardiac opacity projecting over the left lower lobe on the lateral view may represent some combination of consolidation and effusion . The lungs are otherwise clear . The cardiomediastinal silhouette is within normal limits . No pneumothorax .
    OUTPUT:
    
Retrocardiac opacity likely represents a combination of consolidation and effusion . Superimposed infection can not be excluded .