Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left upper lobe cavitary lesion likely reflects a lung abscess secondary to untreated aspiration pneumonia ; however , the differential also includes tuberculosis and septic embolus . Normal cardiomediastinal and hilar contours . Normal pleural surfaces . No acute pneumonia , pleural effusion , or pneumothorax .
    OUTPUT:
    
Left upper lobe cavitary lesion likely reflects a lung abscess secondary to untreated aspiration pneumonia , but tuberculosis must be ruled out .