Bilateral fumarate hydratase deficient renal cell carcinoma in a patient with hereditary leiomyomatosis and renal cell cancer syndrome

Introduction Patients with hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome have high risks of uterine and cutaneous leiomyomas and renal cell carcinoma (RCC), which are caused by germline mutation of the fumarate hydratase (FH) gene. RCC lesions are mostly high‐grade tumors with a poor prognosis. Case presentation A 37‐year‐old man who had previously undergone treatment for a left RCC was referred to our hospital with a diagnosis of right RCC. Robot‐assisted partial nephrectomy was performed, and the pathological diagnosis revealed fumarate hydratase (FH)‐deficient RCC. The left RCC, which was originally diagnosed as mucinous tubular and spindle cell carcinoma, was reviewed and diagnosed as FH‐deficient RCC. The patient's father and uncle both died of RCC, and the father's tumor was also immunohistochemically proven to be FH‐deficient RCC. Conclusion HLRCC‐related RCC should be considered in a differential diagnosis of young patients with a family history of RCC.