Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided . There is a large retrocardiac opacity containing ___ air - fluid level which is compatible with a hiatal hernia . The previously detected pleural effusion has resolved . The lungs are clear . The cardiomediastinal silhouette is normal . ___ azygous fissure is noted . Bony structures are intact .
    OUTPUT:
    
Hiatal hernia , otherwise unremarkable .