Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest are provided . There is a large retrocardiac air and soft tissue density structure , compatible with known large hiatal hernia . The lungs are clear . No signs of pneumonia or CHF . No effusion or pneumothorax . The mediastinal contour is normal . The overall heart size appears stable . Bony structures are intact .
    OUTPUT:
    
Large hiatal hernia . Otherwise , normal .