Medulloblastoma in Adolescents and Young Adults: Molecular Subgroups, Prognostic Biomarkers, and Age-Specific Therapeutic Challenges

Medulloblastoma is the most common malignant brain tumor in children, but it presents distinct challenges when occurring in adolescents and young adults (AYAs, aged 15-39 years). Recent molecular profiling has identified four principal medulloblastoma subgroups-WNT-activated, SHH-activated, Group 3, and Group 4-each demonstrating unique biological characteristics and clinical outcomes. AYA patients exhibit age-specific molecular patterns and therapeutic responses substantially different from those of younger children. This review synthesizes current evidence regarding epidemiology, diagnostic challenges, molecular characterization, risk stratification, treatment modalities, and outcomes specific to AYA medulloblastoma patients, highlighting the critical need for age-adapted therapeutic strategies and dedicated clinical research in this underserved population.