[Central Type Squamous Cell Lung Cancer Incidentally Found by the Treatment of Pneumothorax;Report of a Case].

: A 69-year-old man who arrived at our hospital by ambulance with dyspnea was diagnosed with pneumothorax. The chest was drained, but the left lung failed to expand due to air leakage. A pulmonary fistula in the left lower lobe identified by video-assisted thoracic surgery was repaired. Postoperative chest radiography showed inadequate expansion of the left upper lobe. Bronchoscopy revealed an obstruction of the left upper bronchus that was pathologically diagnosed as squamous cell carcinoma. Enhanced computed tomography revealed a central tumor with atelectasis of the left upper lobe, and a stained node in the left lower lobe. Clinical T4N1M0 stage III A lung cancer was confirmed. The patient was treated with concurrent chemoradiotherapy. It was likely that the lung cancer in the upper bronchus caused the atelectasis, leading secondary expansion of the lower lobe and the rupture of a bulla.