Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded . A 2 .0 cm rounded mass is again noted in the left upper lung , similar to prior exam . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is unremarkable .
    OUTPUT:
    
Stable appearance of 2 .0 cm left upper lung mass .