Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mildly enlarged . The mediastinal and hilar contours appear unchanged . There is similar patchy opacification at the left lung base , probably involving the left lower lobe with left lateral pleural thickening . A smooth defect along the course of the right posterior fifth rib appears unchanged . The right lung remains clear aside from patchy unchanged right infrahilar opacity , again suggesting minor atelectasis or scarring . There is no pleural effusion or pneumothorax . No definite evidence of pneumonia .
    OUTPUT:
    
Stable chronic - appearing findings including left basilar scarring and pleural thickening ; no definite evidence of pneumonia .