Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Large mediastinal mass shifting trachea leftwards with patent tracheal stent . Tip of right pleural drain impinges on mediastinum . No pneumothorax or pulmonary edema . Interval increase of bibasilar atelectasis , right greater than left with new small right pleural effusion . Heart size and left mediastinal contour are normal . No bony abnormality .
    OUTPUT:
    
1 . Mild increase in bibasilar atelectasis , right greater than left . No pneumothorax . 2 . New small right pleural effusion .