2026 年 13 巻 p. 41-47
Myxoid glioneuronal tumor is a newly included entity in the 2021 World Health Organization classification of central nervous system tumors, based on both pathological and molecular evidence, characterized by platelet-derived growth factor receptor alpha mutations. A 23-year-old female presented with intermittent visual field abnormalities and dizziness. Magnetic resonance imaging revealed a 2-cm mass occupying both foramens of Monro, leading to non-communicating hydrocephalus. Endoscopic surgery via the transcortical approach achieved gross total resection of the tumor. Postoperatively, she developed cognitive dysfunction involving recent memory disturbance and progressive ventricular dilation, necessitating a ventriculoperitoneal shunt, which led to significant cognitive recovery. Histopathological analysis confirmed myxoid glioneuronal tumor with a platelet-derived growth factor receptor alpha p.K385L mutation. A review of 23 cases, including ours, indicates that surgical resection is the preferred treatment and is generally associated with a favorable prognosis. However, recurrence and meningeal dissemination have been reported in some cases, emphasizing the need for long-term follow-up. Myxoid glioneuronal tumor is frequently located close to critical structures like the fornix, so careful surgical planning is essential to balance maximal resection with functional preservation. Endoscopic techniques offer advantages for deep-seated lesions by minimizing cortical damage while allowing adequate tumor resection. Further studies are needed to establish the optimal treatment strategies and clarify the long-term prognosis of myxoid glioneuronal tumor.