Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) primary spontaneous pneumothorax ?
    ### Response:
    Primary spontaneous pneumothorax is an abnormal accumulation of air in the space between the lungs and the chest cavity (called the pleural space) that can result in the partial or complete collapse of a lung. This type of pneumothorax is described as primary because it occurs in the absence of lung disease such as emphysema.
    