Autoimmune encephalitis related to nivolumab followed by tumor regression.

Immune checkpoints inhibitors have shown a remarkable improvement in overall survival of stage IV renal cell carcinoma patients. Nevertheless, there is a wide range of immune-related adverse events (IRAE) that arise from these revolutionary treatments. Autoimmune encephalitis is a rare but severe central nervous system IRAE in these cancer patients. The severities of these IRAEs preclude patients from continuing immunotherapy treatment. Few cases of autoimmune encephalitis with immunotherapy have been described in the literature and optimal clinical management of these events as well as patient's immune-mediated response after treatment suspension is still unclear. Here, we report a case of a 67 years-old woman with stage IV renal cell carcinoma under treatment with nivolumab who developed autoimmune encephalitis. After high doses of corticosteroids patient's condition improved significantly with full recovery after 5 days of treatment. Even though nivolumab was not reinstalled, a persistent response of her oncologic disease was evidenced. We expect that this case can contribute to the existing literature of both subjects, the management of autoimmune encephalitis as grade IV immune related adverse event and the responses of immune checkpoint inhibitors after IRAE.