Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since prior , there is mild increase in size of a moderate right pneumothorax , which measures approximately 2 .1 cm . A right pigtail is unchanged in position . The left lung is clear . Cardiomediastinal and hilar contours are normal . There is no mediastinal shift or diaphragmatic flattening to suggest tension physiology .
    OUTPUT:
    
Mild increase in size of moderate right apical pneumothorax .