Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest were provided . Lungs are clear bilaterally . A retrocardiac opacity containing an air - fluid level is compatible with a hiatal hernia . This hiatal hernia was seen previously . No pleural effusion or pneumothorax . Bony structures are intact . Heart size is within normal limits . Mediastinal contour is normal .
    OUTPUT:
    
Hiatal hernia , otherwise unremarkable .