Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a persistent left pleural effusion , minimally decreased compared to the prior study with improved aeration of the left lung base . There is persistent airspace opacity in the left upper lobe consistent with the findings on the prior chest CT . The left hilar mass is partially obscured by this airspace opacity but appears grossly unchanged . The right lung appears grossly clear . No right - sided pleural effusion . Severe degenerative changes in the right shoulder . .
    OUTPUT:
    
Persistent left pleural effusion . Unchanged left hilar mass . Slightly increased airspace opacity in the left upper lung .