Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were obtained . Subtle opacity at the left lung base could represent pneumonia within the left lower lobe . There is no large pleural effusion . The right lung appears clear . Heart size is normal . Mediastinal contour is unremarkable . Bony structures are intact .
    OUTPUT:
    
Subtle opacity at the left lung base is concerning for an early pneumonia in the left lower lobe .