Only three cycles of nivolumab showed remarkable durable response and reversible myeloradiculoneuropathy in a patient with metastatic papillary renal cell carcinoma type 2

INTRODUCTION: The efficacy of nivolumab for non-clear cell renal cell carcinoma is still unclear. We present a rare case of metastatic papillary renal cell carcinoma remarkably responded to nivolumab but developed myeloradiculoneuropathy as immune-related adverse event. CASE PRESENTATION: The patient had previously undergone radical nephrectomy for right renal mass and was diagnosed as papillary renal cell carcinoma type 2, pT3bN0M0. Three years after the first surgery, he received 3 mg/kg of nivolumab as a second-line drug for mediastinum lymph nodes and lung metastases. With three cycles of nivolumab, the patient felt progressive weakness of the legs and received two cycles of steroid-pulse therapy based on the diagnosis of myeloradiculoneuropathy. Although nivolumab therapy has been discontinued, the metastases show radiographic complete response at 2 years after the last nivolumab administration without any additional therapy. CONCLUSION: Nivolumab may be a promising treatment option for non-clear cell renal cell carcinoma such as papillary renal cell carcinoma.