Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Normal heart , pleura and mediastinal surfaces . A 5 mm nodule adjacent to the descending aorta projecting over the heart on the frontal view and over a vertebral body on the lateral view is high in density .
    OUTPUT:
    
A 5 mm nodule most likely represents a calcification . Comparison to prior old films is recommended if available . If prior films are not available , CT chest is recommended .