Supplementary Material for: Ganglioglioma Arising from the Septum Pellucidum: Case Report and Review of the Literature

<b><i>Background:</i></b> Gangliogliomas are low-grade neoplasms that typically affect patients under the age of 30 and present with epilepsy and symptoms of mass effect. Here, we report a case of an intraventricular ganglioglioma involving the septum pellucidum in a pediatric patient with history of optic glioma. Only one other pediatric intraventricular ganglioglioma arising from the septum pellucidum has been reported previously. <b><i>Case Report:</i></b> The patient initially presented at 9 months of age with a pilocytic astrocytoma centered on the optic chiasm, treated with chemotherapy and radiation at 3 years of age. Routine follow-up imaging at 13 years of age revealed the development of a mass in the septum pellucidum, which was subtotally resected endoscopically because of its proximity to the fornices. Pathology confirmed a ganglioglioma positive for the BRAF V600E mutation. The tumor residual progressed and was treated with stereotactic radiosurgery. The patient was asymptomatic at her 6-month follow-up visit and the size of the nodule remained stable. <b><i>Literature Review:</i></b> Our review of the 25 previously reported intraventricular gangliogliomas found that their pre-surgical diagnoses were often incorrect, reflecting the difficulty of making the diagnosis with signs, symptoms, and imaging alone. Patients can be reassured that the prognosis is generally favorable following uncomplicated neurosurgical resection.