Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable semi upright frontal chest radiograph demonstrates a mildly enlarged cardiac silhouette . There is a large mass overlying much of the cardiac silhouette and right lower lung , measuring ___ .6 cm wide and consistent with the large hiatal hernia seen on prior CT . The trachea is deviated to the right with splaying of the mainstem bronchi . Pneumomediastinum is better seen in prior CT . No free air is seen higher in the neck . Intra-abdominal free air seen on prior CT is not appreciated on this exam . The lungs are grossly clear , without a large pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Large mass overlying the lower lung , consistent with the large hiatal hernia seen on CT from the same day , with rightward deviation of the trachea and splaying of the mainstem bronchi . 2 . Limited evaluation of known pneumomediastinum . No free air is seen higher in the neck