الفهرس 
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Abstract
Brain tumours are currently the leading cause of cancer-related death in children under the age of 15. They account for about 25% of all pediatric malignancies and are the most prevalent solid tumour in children. Medulloblastoma (MB) is the most frequently occurring malignant brain tumour in children representing up to 20% of all pediatric brain tumours. Children under the age of 10 account for more than 70% of MB cases. MB could occur as a part of cancer predisposition syndromes, such as Li-Fraumeni syndrome, nevoid basal cell carcinoma syndrome and familial adenomatous polyposis.
Diagnosis and risk stratification of MB have mainly been dependent on histopathological examination and clinicoradiological assessment. MB encloses three main morphological subtypes; classic, desmoplastic/nodular and large cell/anaplastic MBs. Risk stratification used to take into consideration different clinicopathological variables such as age at diagnosis, the existence of metastases, the completeness of surgical resection, and histopathological variants.
The current treatment of MB is associated with better survival rates but often with life-long morbidity affecting patients’ quality of life. Iatrogenic morbidity is age-dependent, where in younger patients, craniospinal irradiation (CSI) carries troublesome morbidity, in older children, surgery results in substantial complications. Survivors of childhood MB commonly suffer from a variety of severe, long-term deficits in the functional neuropsychological domains. These severe neuropsychological impairments require further attempts to decrease or postpone the use of CSI for pediatric MB.