Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . There is a subtle retrocardiac opacity containing a tiny locular gas likely representing a hiatal hernia . Lungs are clear without focal consolidation , large effusion or pneumothorax . No signs of congestion or edema . The cardiomediastinal silhouette is normal . Imaged bony structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
Probable hiatal hernia accounting for retrocardiac opacity . Otherwise unremarkable exam .