[A Case of Rheumatoid Arthritis Developed during Treatment with Nivolumab for Renal Cell Carcinoma].

A 66-year-old man underwent nephrectomy for right renal cell carcinoma (cT3bNOMl (PUL)). Thereafter, he was treated with sunitinib for lung metastasis as the first-line therapy for 5 months and then axitinib as the second-line therapy for 2 months. Because lung metastasis progressed despite molecular targeted therapies, nivolumab was used as the third-line treatment. Three months later, he complained of painful stiffness in hands and wrist joints symmetrically. He was diagnosed as having rheumatoid arthritis. Treatment with nivolumab was discontinued and prednisolone and methotrexate were started. Although the painful stiffness in joints was improved l month later, synovitis remained partially 6 months after starting treatment of disease with anti-rheumatic drugs. Therefore, treatment for rheumatoid arthritis was continued. On the other hand, because the lung lesion had progressed 2 months after discontining nivolumab, everolimus was used as the fourth-line therapy.