Seronegative rheumatoid arthritis after combination therapy with ipilimumab and nivolumab for postoperative pancreatic and liver metastases from renal cell carcinoma.

Immune checkpoint inhibitors may cause a wide variety of immune-related adverse events. When arthritis is encountered during immune checkpoint inhibitor administration, seronegative rheumatoid arthritis should be differentiated from other types of arthritis, despite being less frequent.