Nivolumab efficacy in leptomeningeal metastasis of renal cell carcinoma: a case report.

Background: Meningeal carcinomatosis is rare in patients with kidney cancer and treatment options are limited. Few patients treated with systemic approaches have been reported. We describe a case of complete remission of leptomeningeal metastasis in a patient with renal cell carcinoma treated with nivolumab. To our knowledge, this is the first report of nivolumab safety and efficacy in this particular site of metastasis. Case presentation: Our patient was a 60-year-old Caucasian man with bone and lung metastases from renal cell carcinoma. He developed leptomeningeal metastasis and progression of bone and lung lesions after only 2 months of his first-line treatment. He was then treated with nivolumab in second-line setting and experienced a rapid improvement of cancer-related symptoms, complete remission of leptomeningeal and lung lesions, and increased bone mineral density in bone metastasis. The patient did not experience any drug-related toxicity. Conclusions: Meningeal carcinomatosis metastasis from renal cancer is a rare condition. Diagnosis is often challenging: the onset of nonspecific presenting symptoms could be initially attributed to bone involvement, side effects of oncologic therapy, or paraneoplastic syndromes. Our case suggests that nivolumab could be an effective and safe treatment option in patients with pretreated renal cancer with leptomeningeal metastasis.