Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is an abnormal mediastinal convex contour centered at the AP window , better seen on the lateral view in the anterior mediastinum , corresponding with previously - seen mediastinal mass . The lungs are clear without focal consolidation . No pleural effusion or pneumothorax is seen . The heart size normal .
    OUTPUT:
    
Anterior mediastinal mass , better assessed on prior CT .