Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Near complete opacification of the left hemothorax has developed since the radiograph 1 .5 hr prior with increased leftward shift of the mediastinal structures , consistent with lung collapse . At least a small to moderate sized left pleural effusion is present . An intrabronchial mass is seen in the distal left mainstem bronchus with a fiducial marker . The right lung appears clear . No pneumothorax is identified in either lung .
    OUTPUT:
    
Interval development of left lung near - complete , likely related to distal left mainstem intrabronchial mass . Left pleural effusion , at least small to moderate in size .