Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged . Hemidiaphragms are flattened suggesting hyperinflation . There is no definite pleural effusion , although a small effusion would be difficult to exclude on the right , where there is persistent patchy posterior opacification in the right lower lobe . Although the opacity seems more extensive on the frontal view , it is suspected that for the most part opacities have improved given substantial decrease on the lateral view . However , opacification may wax and wane , not discernable on recent radiographs from ___ for example , but present on earlier ones from ___ , with a very similar configuration . Bones show abnormal sclerosis , which suggest metastatic disease , although not otherwise assessed in detail .
    OUTPUT:
    
Waxing and waning opacity in the posterior right lower lobe , which appears overall less dense on this examination compared to the most recent one . The possibility that this appearance may reflect recurrent infection in the same area is not excluded , however .