[Three cases of pneumothorax due to lung cancer].

Spontaneous pneumothorax due to primary lung cancers are increasingly reported as of lung cancer incidence increased. We experienced one lung cancer case with pneumothorax as a primary symptom and two who developed pneumothorax after chemotherapy, among 238 cases of primary lung cancer. In the literature, 76 cases of pneumothorax due to primary lung cancers are described. The mechanism of pneumothorax is discussed.