Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were obtained . As seen previously , there is a large retrocardiac opacity containing multiple air - fluid levels and large bowel haustrations compatible with large hiatal hernia . The lungs appear clear and well expanded . No signs of pneumonia or CHF . No pleural effusion is or pneumothorax . Given the large hiatal hernia , the cardiac size is difficult to accurately assess . The mediastinal contour is unremarkable . The bony structures are intact . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Large hiatal hernia as previously seen . Otherwise , unremarkable .