Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal and hilar contours are normal . At the left lung base , projecting over the left border of the heart , there is a focal dense opacification . No pleural effusion or pneumothorax identified . No osseous abnormality is present .
    OUTPUT:
    
Focal lingular opacity is concerning for pneumonia in appropriate clinical setting .