Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . On the frontal exam , there is slight asymmetric opacity at the left lung base . Lungs otherwise are clear . The cardiomediastinal silhouette is within normal limits . No acute osseous abnormality identified .
    OUTPUT:
    
Subtle left lower lung opacity which could represent pneumonia in the proper clinical setting . Repeat after treatment should be considered to document resolution .