Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since ___ , a focal opacity in the left mid lung may represent pneumonia . However , a mass lesion can not be excluded . Hyperinflated lungs with flattening of the diaphragm . Unchanged bilateral coarse interstitial markings again suggest chronic pulmonary disease . Heart size is normal . No pneumothorax or pleural effusion .
    OUTPUT:
    
1 . Focal opacity in the left mid lung may represent pneumonia . However , mass lesion can not be excluded .