BRAF^V600E mutation is a negative prognosticator in pediatric ganglioglioma

Gangliogliomas are typically low-grade neuroepithelial tumors seen in the pediatric and young adult populations. Despite their often bland histologic appearance, these tumors recur with varying frequencies; however, little data exist that adequately predict ganglioglioma recurrence in children. To identify potential histopathologic features predictive of recurrence-free survival, a series of 53 patients with World Health Organization (WHO) grade I gangliogliomas were evaluated, representing the largest cohort of pediatric gangliogliomas with accompanying histopathologic and survival data. Fifteen patients (28 %) exhibited disease recurrence during the study period. BRAF^V600E immunohistochemistry was performed on 47 of these tumors. Histopathologic features associated with shorter recurrence-free survival included an absence of oligodendroglial morphology, higher glial cell density, microvascular proliferation, and the presence of a high lymphoplasmacytic inflammatory infiltrate. Eighteen tumors (38.3 %) had positive BRAF^V600E staining, which was associated with shorter recurrence-free survival. Collectively, the combined use of histopathologic and molecular features to stratify grade I gangliogliomas into low and high-risk groups provides important information relevant to the management of children and young adults with these rare tumors.