Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographdemonstrates mildly hypoinflated clear lungs . Retrocardiac opacity only see on lateral view is most likely due to overlapping shadows and atelectasis however differential includes pneumonia in the appropriate clinical setting . No pleural effusion or pneumothorax . Heart size , mediastinal contour , and hila are unremarkable . Limited assessment of the upper abdomen is within normal limits .
    OUTPUT:
    
1 . Retrocardiac opacity only seen on lateral view is most likely due to overlapping shadows and atelectasis however differential includes pneumonia in the appropriate clinical setting . 2 . No pneumothorax or widened mediastinum .