Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The external portion of the Pleurx catheter is seen at the edge of the lower left hemithorax . There has been interval decrease of the left - sided pleural effusion . There is no pneumothorax . The right lung is clear . Left upper lobe opacification corresponds with known large mass thought to represent a malignancy , which is displacing the trachea contralaterally .
    OUTPUT:
    
1 . Interval decrease of left pleural effusion . 2 . Large left perihilar malignancy .