Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . There is a focal opacity at the left lung base obscuring the left heart border which is new from prior which is also seen on the lateral . Elsewhere the lungs are clear . The cardiomediastinal silhouette is normal . No acute osseous abnormality detected .
    OUTPUT:
    
Lingular opacity compatible with pneumonia in the proper clinical setting .