Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates low lung volumes which results in bronchovascular crowding . There is an area of increased opacification at the left base , likely representing a combination of pleural effusion and adjacent atelectasis . The right lung is essentially clear . There is an area of increased opacification in the left mid lung zone , an area of presumed lung biopsy . There is a small left - sided apical pneumothorax . Cardiomediastinal and hilar contours are unchanged .
    OUTPUT:
    
Small left - sided apical pneumothorax .