Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size and mediastinal contours are within normal limits . Midline sternotomy wires and mediastinal clips are unchanged . The lungs are clear of consolidation , although a rounded nodular opacity at the left base is present again measuring approximately 2 cm in diameter . It is stable compared to prior exams listed above . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute cardiopulmonary process ; 2 - cm left lower lung nodule is similar in size as compared to prior exams . Prior PET - CT findings and long term stability suggest a benign etiology .