Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Normal heart size , and hilar contours . There is an opacity in the retrosternal space on the lateral view , though this is not a true lateral view and could be related to technique . No focal consolidation , pleural effusion or pneumothorax .
    OUTPUT:
    
Opacity in the retrosternal space on the lateral view , potentially related to suboptimal positioning . Repeat lateral radiograph is recommended to help exclude an anterior mediastinal abnormality such as a thymoma .