Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrates an opacification of the right lung base , which likely represents chronic right pleural effusion , and is essentially unchanged from ___ . The lungs are otherwise clear . The heart is stably enlarged . The mediastinal and hilar contours are unchanged . There is no pneumothorax . There is no left pleural effusion .
    OUTPUT:
    
Opacification of the right lung base present and essentially unchanged since ___ , likely represents a chronic right pleural effusion .