Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal with mild unfolding of the thoracic aorta . Hilar contours are unremarkable . There is increased density at the posterior lung base on lateral view only without definite frontal correlate . Lungs are otherwise clear . Pleural surfaces are clear without effusion pneumothorax .
    OUTPUT:
    
Increased density of the posterior lung base on lateral view only which may represent pneumonia .