Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The small to moderate left apical pneumothorax has increased in size compared to the prior examination . No appreciable atelectasis is identified . The left hemidiaphragm contour is unchanged . The mediastinum remains midline . The heart is not enlarged . Cardiomediastinal silhouette and hilar contours are unchanged . No CHF , focal infiltrate or pleural effusion . Minimal right and likely also left apical pleural thickening is unchanged .
    OUTPUT:
    
Small to moderate left apical pneumothorax has increased slightly in size compared with ___ .