Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . There is an ill - defined left perihilar mass as seen on prior CT exam . Interstitial prominence concerning for lymphangitic carcinomatosis . There is a small left pleural effusion . No pneumothorax . Cardiomediastinal silhouette grossly unchanged . Bony structures appear intact .
    OUTPUT:
    
Left perihilar mass concerning for primary malignancy with interstitial prominence concerning for lymphangitic carcinomatosis .