Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left perihilar opacity is seen . The right lung is clear . There is no pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Left perihilar opacity could be due to pneumonia however , underlying pulmonary lesion / malignancy not excluded . Recommend chest CT .