Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views the chest provided . There is a large retrocardiac opacity containing an air - fluid level consistent with a large hiatal hernia unchanged from prior . No definite evidence for pneumonia or edema . No large effusion or pneumothorax . Overall cardiomediastinal silhouette is stable . Bony structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
Large hiatal hernia . Otherwise unremarkable .