Medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children, with peak incidence between 3–4 and 8–9 years of age, accounting for 16% of pediatric brain tumors and 40% of cerebellar tumors in children, while occurring in 10–15% of cases in infancy. In adults, it is rare, representing less than 1% of central nervous system tumors, with highest incidence in the 20–34 age group. It may be associated with Gorlin and Turcot syndromes, arises from cerebellar neural stem cell precursors, and presents with symptoms such as headaches, nausea, vomiting, and ataxia, often spreading through cerebrospinal fluid. Treatment involves surgery, chemotherapy, and radiation. Histological subtypes include large-cell/anaplastic, desmoplastic/nodular, and medulloblastoma with extensive nodularity. Molecular classification divides it into WNT, SHH, Group 3, and Group 4 subgroups, each with distinct genetic profiles and clinical behavior.