Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Subtle opacity in the left lung base could represent pneumonia with probable subjacent small pleural effusion . Right lung is clear . Cardiomediastinal silhouette is unchanged . No acute osseous abnormality .
    OUTPUT:
    
Left basal opacity concerning for pneumonia with probable adjacent pleural effusion .