2025 年 4 巻 2 号 p. 134-138
Fumarate hydratase-deficient renal cell carcinoma arises from mutations in the fumarate hydratase (FH) gene, representing a rare subset of renal cell carcinoma (RCC). Approximately 19% of patients formerly diagnosed with type 2 papillary RCCs are FH deficient. FH-deficient RCC typically exhibits an aggressive course and is associated with hereditary leiomyomatosis and RCC syndrome in cases with germline mutations. Herein, we report the case involving a 34-year-old Japanese man who experienced a 20-kg weight loss. Computed tomography identified a left renal tumor, leading to a subsequent left nephrectomy. Pathological analysis confirmed FH-deficient RCC. Following diagnosis, the patient underwent treatment with ipilimumab and nivolumab for liver metastasis. Due to disease progression, cabozantinib was administered as second-line therapy, achieving a partial response. Currently, no established standard therapy exists for FH-deficient RCC. Nevertheless, in this case, the multi-kinase inhibitor cabozantinib was effective in combating resistance to immune checkpoint inhibitors.
