[A case of primary lung cancer presenting as pneumothorax]

A 62-year-old man presented pneumothorax as a first manifestation of lung cancer was described. The patient complained right side chest pain and dry cough of 6 days duration. On the day of admission, a chest radiograph showed a large pneumothorax on the right. After 3 days of tube drainage, the lung was re-expanded and a chest radiograph showed a mass density above the right hilum. A chest CT revealed a cavitating tumor of the right upper lobe with a fistula to the pleural space. Right upper lobectomy was performed, and the histology was squamous cell carcinoma. The cause of pneumothorax was bronchopleural fistula secondary to rapid growth of the cancer. Pneumothorax due to primary lung cancer is rare and the prognosis is poor because the cancer was advanced stage or diagnosis of cancer was delayed in the literature review. Lung cancer should always be considered as a possible cause of pneumothorax, and it is important to diagnose lung cancer as soon as possible.