Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A moderate sized right pneumothorax is demonstrated with atelectasis of the right lung base . There is minimal leftward shift of midline structures . Heart size is normal . Mediastinal and hilar contours normal . Pulmonary vasculature is normal . Left lung is clear . No pleural effusion is identified . There are no acute osseous abnormalities . A right - sided VP shunt catheter is partially imaged .
    OUTPUT:
    
Moderate size right pneumothorax with mild leftward shift of mediastinal structures worrisome for tension .