Pneumothorax manifesting primary lung cancer.

Pneumothorax is a rare lung cancer manifestation. We report 2 patients in which pneumothorax occurred as a first manifestation of lung cancer. Postoperative lung tissue examination after pneumothorax showed lung cancer by chance. One patient had dissemination suspected due to ruptured bulla with adenocarcinoma. Both immediately underwent additional lobectomy with mediastinal lymphadenectomy after lung cancer was diagnosed, but we detected lung cancer recurrence in the bottom of the pleural cavity on the same side some 11 months after radical surgery in the patient suspected of dissemination. We could resect it completely, followed by adjuvant radiotherapy. The possibility of lung cancer should thus be considered in pneumothorax patients, even if middle-aged.