Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . The right lung is clear . There is a retrocardiac opacity obscuring the left hemidiaphragm , likely pneunonia vs atelectasis . There may be a tiny component of pleural effusion . The heart size is top normal . The cardiomediastinal and hilar contours are unremarkable . Sclerotic intramedullary lesion in the right humeral neck is unchanged and likely represents an enchondroma .
    OUTPUT:
    
Left lung base opacity consistent with pneumonia vs atelectasis . There may be an associated tiny pleural effusion .