Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . On the lateral view only , there is retrocardiac opacity which potentially raises concern for a subtle pneumonia though no definite consolidation is seen on the frontal projection . Please correlate clinically . No large effusion or pneumothorax is seen . The cardiomediastinal silhouette is normal . Imaged osseous structures are intact . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Apparent retrocardiac opacity , question pneumonia .