Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to prior chest radiograph , there has been increased opacification in the left lower lobe and left perihilar region . The appearance of the right lung is grossly stable noting apical opacity likely due to prior radiation . The cardiomediastinal silhouette is normal . There is no pleural effusion or pneumothorax . Views of the upper abdomen are unremarkable .
    OUTPUT:
    
Increased opacification in the left lower lobe and perihilar region , concerning for pneumonia . Please note that interval followup after treatment will be necessary especially in light of patient 's history of malignancy .