Medulloblastoma SNOMEDCT_US:83217000 HP:0002885 NCIT:C3222 UMLS:C0025149 Medulloblastoma is a highly malignant primary brain tumor that originates in the cerebellum or posterior fossa and belonging to the family of cranial primitive neuroectodermal tumors. A rapidly growing embryonic tumor arising in the posterior part of the cerebellar vermis and neuroepithelial roof of the fourth ventricle in children. More rarely, medulloblastoma arises in the cerebellum in adults. SNOMEDCT_US:443333004 Malignant neoplasm of the central nervous system