SURG-26. Diffuse leptomeningeal glioneuronal tumor: A systematic review of clinical presentation, treatment, and outcomes

Abstract Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare central nervous system neoplasm first defined in the 2016 WHO classification. Due to its rarity, most available data are limited to case reports or small series, and clinical management remains inconsistent. We conducted a PRISMA-compliant systematic review of DLGNT cases published between 2016 and June 2024 using PubMed, Embase, Scopus, Cochrane Library, and Google Scholar. A total of 76 patients from 42 publications were included. Data on demographics, imaging, pathology, molecular findings, treatment, and survival were extracted. Kaplan–Meier analysis and subgroup comparisons were performed. One institutional case was added. The overall cohort was predominantly pediatric (72%), with frequent spinal dissemination (61%) and hydrocephalus (62%). BRAF fusion was the most common molecular alteration. No significant differences in overall survival were found by age group, BRAF status, or treatment modality (all p > 0.99). In subgroup analysis by surgical extent, patients who underwent surgical resection (n = 19) showed a longer median progression-free survival (PFS; not reached) than those who had biopsy only (n = 57, median PFS = 19 months), though this difference was not statistically significant (p = 1.00). Our institutional case involved a young adult initially misdiagnosed with tuberculous meningitis and later confirmed as DLGNT via biopsy. The patient underwent craniospinal irradiation (36 Gy in 20 fractions) followed by 12 cycles of temozolomide chemotherapy. After 24 months of disease stability, the patient developed peritoneal seeding confirmed as DLGNT and died 29 months after diagnosis. DLGNT displays wide clinical and molecular heterogeneity, often with delayed diagnosis. Although surgical resection may offer longer PFS, current evidence is insufficient to reach statistical significance. This review highlights the need for early recognition, standardized management, and further investigation, especially in atypical disease courses such as extracranial dissemination.