Complete response of hereditary leiomyomatosis and renal cell cancer (HLRCC)-associated renal cell carcinoma to nivolumab and ipilimumab combination immunotherapy by: a case report.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare autosomal dominant disorder that results from a germline mutation in the fumarate hydratase gene (FH). Individuals with FH mutations are at risk of developing renal cell carcinoma (RCC). Patients with HLRCC-associated RCC (HLRCC-RCC) have aggressive clinical courses, but there is as yet no standardized therapy for advanced HLRCC-RCC. We report an aggressive RCC case in a 49-year-old man. Nine weeks after undergoing a total nephroureterectomy of the right kidney, he had a metastasectomy at port site. Within 14 weeks of the initial surgery, multiple recurrent tumors developed in the right retroperitoneal space. The pathological diagnosis was FH-deficient RCC. Genetic testing identified a heterozygous germline mutation of FH (c.641_642delTA), which confirmed the diagnosis of HLRCC-RCC. He received combination therapy with the immune checkpoint inhibitors (ICIs) nivolumab and ipilimumab as the first-line therapy. After 31 weeks of ICI treatment, a complete response was achieved. The disease-free condition has been prolonged for 24 months since the initial surgical treatment. This is the first case report of successful treatment of HLRCC-RCC with nivolumab plus ipilimumab. This combination immunotherapy is expected to be an effective approach to treat patients with advanced-stage HLRCC-RCC.