Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . There is a large retrocardiac opacity again seen containing air compatible with a large hiatal hernia . No focal consolidation concerning for pneumonia . No effusion or pneumothorax . The heart is top - normal in size . Mediastinal contour is unchanged . Bony structures are intact . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Large hiatal hernia .