Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Minimal increased opacity at left lung base is probably due to superimposition of breast tissue rather than pneumonia . Right lung is unremarkable . Mediastinal and cardiac contours are normal . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
Minimal left lower lobe opacity is probably due to superimposition of breast tissue . Standard PA and lateral views may be helpful to exclude a pneumonia in this region , if warranted clinically .