Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest . Vague opacity projecting over the anterior left 1st rib is compatible with patient 's known lung mass . Left lower lobe pulmonary nodule also seen in the retrocardiac region on the frontal exam . There is a new opacity at the left lung base laterally on the frontal view which is not clearly delineated on the lateral exam . Cardiomediastinal silhouette is within normal limits . No acute osseous abnormality detected .
    OUTPUT:
    
Faint left basilar opacity seen laterally not well seen on the lateral view . All this could be due to atelectasis , developing infection is not completely excluded . Known left apical lesion and left lower lobe and nodule as previously characterized .