Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Small left pleural effusion and / or pleural scarring is noted . There appears to be pleural calcification . There is biapical pleural thickening . There is no consolidation or pneumothorax . Cardiomediastinal silhouette is normal size .
    OUTPUT:
    
Small left lung base pleural scarring and / or pleural effusion of unknown chronicity . Lungs are clear .