[A Case of Intestinal Fistula Associated with Small Intestinal Metastasis from Small Cell Lung Carcinoma].

A 53-year-old man who complained of dyspnea and prolonged cough visited to our hospital. Computed tomography (CT)revealed massive tumors of right lung and small intestine. CT-guided fine-needle aspiration(FNA)on lung lesion was performed and the lung tumor was diagnosed as small cell carcinoma. We subsequently performed surgical resection for the tumor of small intestine, but part of tumor lesion remained due to pelvic wall invasion. The resected tumor was diagnosed as metastasis from lung carcinoma by histopathological examination. After surgery the patient was treated with atezolizumab and carboplatin-etoposide chemotherapy, but the remnant metastasis caused intestinal fistula. Treatment was continued carefully with fistula management using pouches. Although the fistula was closed during chemotherapy response, it recurred after discontinuation of treatment due to severe adverse events. The patient died 325 days after the surgery.