Disseminated glioneuronal tumors occurring in childhood: treatment outcomes and BRAF alterations including V600E mutation

Disseminated glioneuronal tumors of childhood are rare. We present a retrospective IRB-approved review of the clinical course and frequency of BRAF mutations in disseminated glioneuronal tumors at two institutions. Defining features of our cohort include diffuse leptomeningeal-spread, often with a discrete spinal cord nodule and oligodendroglioma-like histologic features. Patients were identified through a pathology database search of all cases with disseminated low-grade neoplasms with an oligodendroglioma-like component. De-identified clinical information was collected by chart review and all imaging was reviewed. We retrieved the results of targeted genomic analyses for alterations in BRAF. Ten patients (aged 2-14 years) were identified from the Dana-Farber/Boston Children's Hospital and the Royal Children's Hospital, Melbourne pathology databases. Nine patients received chemotherapy. Eight patients are alive, although three have had episodes of progressive disease. We identified genomic alterations affecting the MAPK pathway in six patients. One patient had a germline RAF1 mutation and a clinical diagnosis of cardio-facio-cutaneous syndrome. BRAF duplications were identified in four and BRAF V600E mutation was identified in one. These data support the presence of targetable genomic alterations in this disease.