A Case of a Fumarate Hydratase Deficient Astrocytoma in Association With a Germline Fumarate Hydratase Mutation With Review of the Literature: Considerations for Patients With Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC) Syndrome.

Diffuse adult-type gliomas are delineated based on their molecular composition including the presence or absence of mutations in isocitrate dehydrogenase 1 or 2 (IDH1/2), a key enzyme in the citric acid cycle. IDH-mutant tumors are associated with better survival than IDH-wildtype counterparts and can be further subdivided into astrocytoma or oligodendroglioma. Rare gliomas with fumarate hydratase (FH) deficiency have been reported. Given that FH is also a critical enzyme in the citric acid cycle, such tumors seem to be epigenetically similar to IDH-mutant tumors and, despite meeting criteria as IDH-wildtype gliomas per the current recommendations set forth by the World Health Organization, may behave in a manner akin to IDH-mutant neoplasms. Hereditary leiomyoma and renal cell cancer syndrome is associated with cutaneous and uterine leiomyomas and renal cell carcinoma caused by a germline FH alteration. To date, only rare examples of patients with known germline FH mutation subsequently diagnosed with a glioma have been reported. We report a case of a young patient with a glioma harboring features of IDH-mutant astrocytoma without evidence of IDH1/2 alterations. After the identification of cutaneous FH-deficient leiomyomas, a retrospective analysis of his brain tumor revealed FH deficiency and a germline FH alteration was ultimately identified after further molecular studies. Although rare, we conclude that FH mutations seem to be part of the spectrum of alterations in diffuse gliomas.