Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal contour is unremarkable . Atherosclerotic calcifications are noted at the aortic knob . Asymmetric enlargement of the left hilar region corresponds to the known posterior perihilar left lower lobe superior segment mass which is somewhat partially obscured on this exam , but appears grossly unchanged compared to the previous CT . Lungs are hyperinflated with emphysematous changes re - demonstrate in the upper lobes . No focal consolidation , pneumothorax , or pleural effusion is demonstrated . No acute osseous abnormality is detected .
    OUTPUT:
    
Left posterior perihilar mass within the superior segment of the left lower lobe is grossly unchanged compared to the previous CT . Emphysema . No pneumonia .