Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . There is no pleural effusion or pneumothorax . A lucency projecting immediately lateral to the right chest wall is probably due to abduction of the arm . A mild pectus excavatum configuration is suspected . There is possibly a trace pleural effusion on the left . A linear opacity projecting over the left upper lung appears unchanged since the remote prior studies suggesting minor scarring .
    OUTPUT:
    
Possible trace pleural effusion on the left , otherwise unremarkable . No evidence of pneumothorax .