[Right S3+4+5 Resection for Lung Cancer with Displaced B3]

A 68-year-old man was referred to our hospital due to an abnormal shadow on chest X-ray film. Chest computed tomography showed a tumor in the right middle lobe. The tumor was 41 mm in size and invaded S3. Preoperative bronchoscopy revealed that right B1, B2, and B3 were branched independently, and B3 was branched from the middle lobe bronchus. A trans-bronchial biopsy was performed and primary lung squamous cell carcinoma was diagnosed (cT2bN0M0, stageⅡA). Although minor fissure was not observed, S3+4+5 resection was performed successfully by dividing pulmonary blood vessels and bronchus before dividing incomplete lobulation (bronchus-first method). The bronchus-first method is useful to avoid not only post-operative air leakage but also accidental cutting of the displaced bronchus by dividing incomplete lobulation frequently associated with bronchial branching abnormalities.