Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Retrocardiac opacity on the lateral view may be due to superimposed vascular structures although subtle consolidation is not excluded in the appropriate clinical setting . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Retrocardiac opacity on the lateral view may be due to superimposed vascular structures , but consolidation is not excluded .