Risk stratification in pediatric dysembryoplastic neuroepithelial tumors: impact of molecular alterations, age, and extent of surgery

Abstract

OBJECTIVE Dysembryoplastic neuroepithelial tumors (DNETs) are usually described as benign, but long-term data clearly show that progression is not rare. Molecular diagnostic techniques have revealed that FGFR1 alterations sit at the core of DNET biology. Importantly, FGFR1 point mutations are known to drive more aggressive behavior in several pediatric gliomas. Likewise, younger children often demonstrate poorer tumor control across multiple low-grade glioma subtypes. These parallels raise the question of whether similar risk patterns exist within DNETs. The aim of this study was to identify reliable predictors of progression in pediatric DNETs by analyzing FGFR1 alteration subtypes, patient age, and extent of resection in order to refine risk stratification. METHODS This retrospective study examined 37 pediatric DNET cases that were confirmed according to the 2021 WHO classification. FGFR1 and BRAF alterations were assessed using droplet digital PCR (ddPCR), and methylation profiling was applied in selected cases. RESULTS FGFR1 alterations were found in nearly 70% of tumors. The most striking finding was the markedly poor prognosis of FGFR1 point mutant cases, with progression rates exceeding 70%, whereas FGFR1 tandem duplications showed a much more indolent course. Age also emerged as a key factor: 45% of patients aged <= 10 years progressed, compared with only 5.9% of older children. Gross-total resection remained the strongest surgical determinant of long-term tumor control. CONCLUSIONS DNETs are biologically heterogeneous. Subtotal resection, FGFR1 point mutations, and younger age clearly identify a higher risk subgroup with shorter progression-free survival. Considering the molecular profile, age, and surgical extent together provides a more accurate framework for clinical decision-making and follow-up planning.