Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . A moderately extensive opacity at least predominantly localizing to the anterior segment of the left upper lobe suggests pneumonia . Elsewhere the lungs appear clear . There are no pleural effusions or pneumothorax .
    OUTPUT:
    
Findings most consistent with pneumonia in the left upper lobe .