Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are within normal limits . Lung volumes are decreased . There is an area of increased opacity at the left lung base . There is also fluid accumulating in the left major fissure . There is no pneumothorax .
    OUTPUT:
    
Increased density at the left lung base concerning for pneumonia with fluid layering in the left major fissure . Short interval followup is recommended upon completion of treatment to document resolution .