Significant response to nivolumab for metastatic chromophobe renal cell carcinoma with sarcomatoid differentiation: a case report

BACKGROUND: The treatment of advanced or metastatic renal cell carcinoma (RCC) has drastically changed since the approval of immune checkpoint therapy. Nivolumab is a treatment option for patients with metastatic RCC, previously treated with targeted antiangiogenic therapy. The efficacy of nivolumab for patients with RCC was established by the Checkmate 025 clinical trial. Chromophobe RCC (CRCC) represents around 5% of RCC cases, but non-clear cell RCC (non-ccRCC) subtypes were excluded from the Checkmate 025 clinical trial. We report a case in which the use of nivolumab as the seventh-line therapy elicited a significant response in the treatment of metastatic CRCC with sarcomatoid differentiation. CASE PRESENTATION: We report a case of a 41-year-old woman with metastatic CRCC with sarcomatoid differentiation. She was treated with sunitinib, pazopanib, everolimus, sorafenib, axtinib, and temsirolimus, but treatment was discontinued because of disease progression or strong adverse events. Seventh-line treatment with nivolumab was initiated and significant clinical improvement was noted after 4 cycles. The treatment was well-tolerated with no significant side effects and the patient continues with nivolumab treatment at present. CONCLUSIONS: Nivolumab may be an attractive treatment option for non-ccRCC patients with sarcomatoid differentiation that exhibited aggressive characteristics and poor prognosis. Further investigation is warranted.