Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP single view of the chest has been obtained with patient in sitting semi-upright position . Analysis is performed in direct comparison with the next preceding similar study obtained 4 hours earlier during the same day . The findings are completely unchanged with a 2 - 3 cm wide apical pneumothorax on the right side . Also , some local chest wall emphysema is seen in the right lower neck and shoulder area , also unchanged . No new pulmonary or cardiovascular abnormalities identified .
    OUTPUT:
    
Stable appearance of previously identified apical pneumothorax for the last 4 hours .