Concurrent combination of irradiation and immune checkpoint inhibitor for recurrent pleomorphic carcinoma of the lung.

We report the case of a 49-year-old patient who developed brain, sternal, and spine metastases almost simultaneously after the radical resection of a yp-T4N0M0 pulmonary pleomorphic carcinoma of the right upper lobe following induction chemotherapy. The left occipital brain metastasis was surgically removed and followed by radiation therapy. The sternal and vertebral metastases were treated with radiation therapy. Concurrently, the immune checkpoint inhibitor nivolumab was administered. After 12 cycles of nivolumab, the two bone metastases were well-controlled. However, the brain metastasis recurred and was surgically removed again. We were able to investigate the tumor-infiltrating lymphocytes in brain metastases resected before and after radio-immunotherapy. The results revealed the increased number of CD8- and CD68-positive cells after the combined therapy compared with before the therapy. In addition, the high-level expression of program death-ligand 1 was maintained in the brain metastasis.