Bridging pediatric and adult neuro-oncology: Insights into adolescents and young adults (AYA) central nervous system tumors.

Adolescents and young adults (AYA) with central nervous system (CNS) tumors represent a distinct and historically underrecognized population that spans the traditional pediatric-adult oncology divide, with unique biological, clinical, and survivorship considerations. The central nervous system (CNS) tumor spectrum in this age band is thus broad: pediatric-type entities driven by MAPK-pathway alterations, adult-type IDH- and H3-mutant gliomas, embryonal tumors, ependymomas, and intracranial germ cell tumors all appear, and prognosis and treatment are increasingly determined by molecular subtype rather than chronologic age. Integrated workflows combining neuroimaging, histopathology, and molecular profiling now anchor diagnosis and risk stratification. Treatment strategy - surgery, radiotherapy, systemic and targeted agents, and emerging immunotherapies - must balance efficacy against the cumulative late effects that come with it: neurocognitive change, endocrinopathy, vasculopathy, fertility loss, psychosocial disruption, and gaps in transition of care. Germline predisposition syndromes contribute meaningfully to disease biology and have implications for treatment, surveillance, and family screening. This review synthesizes the current evidence across diagnosis, treatment, survivorship, and predisposition, and argues for the consolidation of AYA neuro-oncology as a distinct discipline supported by dedicated trial access and survivorship infrastructure.