原発不明転移性胸壁癌摘出2年後に原発巣と診断された肺癌

Lung Cancer Diagnosed as Primary Site Two Years after the Resection of the Thoracic Wall Cancer of Unknown Primary

原発不明癌（CUP）は予後不良な悪性腫瘍で，生存期間中央値は6～10ヵ月と報告されている．われわれは胸壁にのみ癌病巣を認めるCUPの摘出術を行い，摘出2年後に肺原発巣が確認された症例を経験したので報告する．

A 73-year-old man was referred to our department because of the left chest wall tumor. Computed tomography （CT） showed a chest wall tumor. The chest wall resection was carried out and the tumor was diagnosed as metastatic squamous cell carcinoma of unknown primary. The elevated serum level of carcinoembryonic antigen （CEA） was normalized after the surgery. Two years after the resection, the serum level of CEA elevated again and CT showed the pulmonary tumor 20 mm in diameter in the left upper lobe adjoining to the mediastinal pleura. The partial resection of the left upper lobe with mediastinal pleura was carried out. Pathological examination revealed this tumor to be the primary site of the previously resected chest wall tumor.