Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Small right apical pneumothorax measuring up to 2 .3 cm in greatest extent has slightly increased in size compared to the previous study . Remainder of the lungs are clear . The cardiac , mediastinal and hilar contours are unchanged , and no leftward shift of mediastinal structures is present . There is no pleural effusion . No acute osseous abnormality is visualized .
    OUTPUT:
    
Small right apical pneumothorax , minimally increased in size compared to the previous study .