Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The mediastinal and hilar contours are unremarkable and unchanged . The pulmonary vasculature is not engorged . Ring - like 5 .5 cm opacity within the right lower lobe is compatible with the known malignancy , and contains ___ fiducial markers within it . Compared to the previous radiograph , the central portion of this mass is now radiolucent . No new focal consolidation , pleural effusion or pneumothorax is present . There mild degenerative changes seen in the thoracic spine
    OUTPUT:
    
5 .5 cm right lower lobe mass compatible with known malignancy contains 2 fiducial markers within it and now demonstrates central lucency , new from the previous radiograph . No acute cardiopulmonary abnormality otherwise demonstrated .