Surgical treatment of metastatic brain tumor from gastric cancer during therapy with nivolumab: A case report

•Nivolumab is a new immunological checkpoint inhibitor, and was approved for use against advanced gastric cancer.•The efficacy of nivolumab against metastatic brain tumor from gastric cancer has remained unknown.•We report the surgical case of a patient with refractory metastatic brain tumor from gastric cancer following nivolumab treatment.•Only our patient underwent surgical resection of the tumor during therapy with nivolumab.•Surgical resection of a metastatic brain lesion from gastric cancer should be considered in patients unresponsive to nivolumab therapy.