[Synchronous multiple lung cancer including a lesion with a thin-walled cavity; report of a case].

A 79-year-old woman underwent video-assisted thoracic surgery (VATS)-left S6 segmentectomy for left lung cancer (papillary adenocarcinoma, pT1N0M0, stage IA), and were followed-up at our hospital. Chest X-ray and chest computed tomography (CT) showed ground-glass opacity (GGO) with thin-walled cavity in the right S1, 3 cm in size and small nodule in the right S2, S3 at 1st operation. The shadow in S1 was not changed but nodular lesion in S2, S3 enlarged 7 months later. CT-guided biopsy revealed well differentiated adenocarcinoma VATS-right upper lobectomy was performed and both lesions were diagnosed as "adenocarcinoma with mixed subtypes (BAC : acinar type), synchronous multiple lung cancer one of which formed thin-walled cavity" histopathologically. The patient was discharged on 20th-postoperative day and alive without any signs of recurrence for 16 months post-operatively.