The Significant Antitumor Activity of Nivolumab in Lung Adenocarcinoma with Choriocarcinomatous Features.

We report the case of a 60-year-old Japanese man with a metastatic brain tumor that caused ataxia. As a consequence of resection of a cerebellar tumor, the tumor was diagnosed as a poorly differentiated adenocarcinoma with choriocarcinomatous features. The patient underwent bronchoscopy, leading to a diagnosis of the same histology as the brain tumor. After the administration of first-line chemotherapy and maintenance therapy due to progressive disease, he was given nivolumab and obtained a partial response; however, 11-months later, computed tomography showed tumor progression. Our experience suggests that nivolumab has strong activity, even in patients with a rare form of lung cancer.