Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is no evidence of pneumothorax . Large left upper lobe irregularly marginated mass corresponds to mass seen on recent PET CT . There is no other focal consolidation or pleural effusion . The cardiomediastinal silhouette is unremarkable . Visualized osseous structures are unremarkable .
    OUTPUT:
    
No pneumothorax . Known left upper lobe mass .