Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded and clear . The cardiac silhouette is top normal in size . There is a stable prominence of the superior mediastinal contour reflecting a known left thyroid goiter . No pleural effusion or pneumothorax is present . The patient is status post right mastectomy .
    OUTPUT:
    
No acute intrathoracic process .