Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Right lung is clear . There is volume loss in the left lung with perihilar opacity which could reflect patient 's known malignancy . Difficult to exclude a superimposed pneumonia . No large effusion or pneumothorax is seen . The overall cardio mediastinal silhouette appears grossly stable from the prior CT allowing for differences in modality .
    OUTPUT:
    
Left perihilar opacity could represent patient 's known malignancy though a superimposed pneumonia difficult to exclude .