Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The small left apical pneumothorax continues to exist , unchanged from the prior radiograph . A small left pleural effusion is stable . Lungs are clear of focal opacities concerning for infectious process . Cardiomediastinal silhouette and hilar contours are stable .
    OUTPUT:
    
Unchanged left apical pneumothorax .