Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a small left pleural effusion , increased since the prior study , with overlying atelectasis . Patchy left base retrocardiac opacity may relate to combination of pleural effusion and atelectasis , underlying consolidation can not be excluded in the appropriate clinical setting . The right lung is clear . There is no right pleural effusion . No evidence of pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Small left pleural effusion with overlying atelectasis . Patchy left base retrocardiac opacity may relate to a combination of pleural effusion and atelectasis , but underlying consolidation is not excluded .