Extraventricular Neurocytoma: Clinical Investigation of Heterogenous Prognosis

BACKGROUND: Extraventricular neurocytoma (EVN) is an extremely rare neuronal neoplasm that arises outside the ventricle. The clinical implication of the heterogenous prognosis of this rare tumor has not yet been clarified. Herein, we analyzed our institutional series of EVN. METHODS: A total of eight consecutive cases were enrolled and investigated. The prognosis of EVN was analyzed and compared to that of central neurocytoma (CN). RESULTS: There were two male and six female patients, and the median age was 36.5 years. The median tumor size was 38 mm, and the most common location of the tumor was the frontal lobe (3, 37.5%), followed by the parietal and temporal lobes. In brain imaging, four (50%) tumors showed peritumoral edema and three (37.5%) tumors showed calcification. All patients underwent gross total resection, and two (25%) underwent adjuvant radiotherapy. The 5-year overall survival (OS) was 55.6%, and the 2-year progression-free survival (PFS) was 42.9%. The OS and PFS of EVN were poor compared to those of CN. Although EVN is a single disease entity, individual patients showed varying prognosis. One patient showed no recurrence during the 7-year follow-up period; however, another patient had a recurrence 4 months after surgery and died 2 years later. CONCLUSION: EVN may be a heterogenous disease entity. Additional cases with long-term followup are needed to develop optimal management protocols.