Hereditary leiomyomatosis and renal cell cancer without cutaneous manifestations in two Japanese siblings.

Hereditary leiomyomatosis and renal cell cancer is a rare genetic disorder characterized by cutaneous and uterine leiomyomatosis, and an aggressive type 2 papillary renal cell carcinoma. The disease is caused by a germline mutation in the fumarate hydratase gene. We report a familial hereditary leiomyomatosis and renal cell cancer in two siblings. A 34-year-old woman underwent nephrectomy for treatment of a renal cell carcinoma. The patient's sister had been diagnosed with renal cell carcinoma at 28 years-of-age and died of the disease. Neither sister had apparent skin tumors. Histopathology of the renal cell carcinomas of the siblings showed tubulocystic and papillary architectures with high nuclear grades. Immunostaining showed no fumarate hydratase expression in either tumor. Genomic DNA sequencing of the patient showed a germline mutation in the fumarate hydratase gene (c.675delT). Although there is no epidemiological information on Asian hereditary leiomyomatosis and renal cell cancer, physicians should be aware that typical cutaneous leiomyomatosis might not always be present in patients with hereditary leiomyomatosis and renal cell cancer.