上大静脈症候群をきたした縦隔由来大細胞神経内分泌癌

Superior Vena Cava Syndrome due to Large Cell Neuroendocrine Carcinoma Originated in the Mediastinum

縦隔腫瘍による上大静脈症候群で著しく生活の質（QOL）が低下した53歳，男性に対して，治療と診断をかね，準緊急で人工心肺使用下に腫瘍および上大静脈を合併切除し，人工血管で置換した．最終病理診断は大細胞神経内分泌癌（large cell neuroendocrine carcinoma：LCNEC）であり，術後経過も含めて報告する．

We report a case of a 53-year-old man with superior vena cava （SVC） syndrome due to large cell neuroendocrine carcinoma （LCNEC） in the mediastinum. His chief complaint was general fatigue. On physical examination, both jugular veins were distended and his face and bilateral upper limbs were swollen. Enhanced chest computed tomography （CT） scan demonstrated a heterogenous tumor of approximately 50 mm in diameter in the middle mediastinum, which infiltrated into the SVC and right atrium, and caused SVC syndrome. Since SVC syndrome developed rapidly, the tumor was resected and the occluded SVC was replaced with a ringed polytetrafluoroethylene graft under cardiopulmonary bypass. After surgery, SVC obstruction was resolved with improvement of the initial symptoms. The patient had an uneventful recovery and was discharged from our hospital. The tumor was diagnosed as LCNEC histologically. He received postoperative adjuvant systemic chemotherapy. Unfortunately, he died of extensive brain and bone metastasis 10 months after the operation. However, we believe that surgical relief from SVC syndrome improved quality of the rest of his life.