Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . There is a subtle opacity in the left lower lung sillouhetting the left heart border , possibly representing early pneumonia in the lingula . Otherwise , lungs are clear . There is no pleural effusion , or pneumothorax . The cardiomediastinal and hilar contours are normal .
    OUTPUT:
    
Possible lingular pneumonia .