Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A large right hilar mass with associated post-obstructive atelectasis , including volume loss with moderate elevation of the right hemidiaphragm is more discretely visualized with a marked reduction of pleural effusion , but opacification has substantially improved in the right lower lung , either due to rapidly clearing atelectasis or interval thoracentesis . The left lung remains clear aside from streaky left basilar opacity suggesting minor atelectasis . The lateral view demonstrates that a major mass - like opacity is predominantly posterior and perhaps centered primarily in the right lower lobe , although not completely characterized . A vague nodular focus projects over the left upper hemithorax , in the same location as seen previously , but not as well visualized and potentially decreased . There is no pneumothorax . The bony structures are unremarkable aside from mild - to - moderate rightward convex curvature .
    OUTPUT:
    
Substantial reduction in right lower lung opacification without evidence for pneumothorax . Findings worriseomf for a large right perihilar mass with associated extensive atelectasis , concerning for underlying malignancy .