Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest . Heart size and cardiomediastinal contours are normal . Small left base opacity could represent atelectasis or infection . Rounded left upper lobe opacity and is concerning for a pulmonary mass . No pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Small left base opacity , consistent with atelectasis or infection . 2 . Round left upper lobe lesion concerning for pulmonary mass . Nonemergent chest CT is recommended for further evaluation .