medulloblastoma

n. (Oncology) malignant tumor of the cerebellum composed of undifferentiated neuroglia (primarily affects children)

Medulloblastoma is a highly malignant primary brain tumor that originates in the cerebellum or posterior fossa.Originally considered to be a glioma, medulloblastoma is now known to be of the family of cranial primitive neuroectodermal tumors (PNET).Tumors that originate in the cerebellum are referred to as infratentorial because they occur below the tentorium, a thick membrane that separates the cerebral hemispheres of the brain from the cerebellum. Another term for medulloblastoma is infratentorial PNET. Medulloblastoma is the most common PNET originating in the brain.
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Med·ul·lo·blas·to·ma n. A glioma consisting of neoplastic cells that resemble the undifferentiated cells of the primitive neural tube. [more]Medulloblastoma - Community and Resources

A type of brain tumor.

[MED-yoo-lo-blas-TOE-ma]
A malignant brain tumor that begins in the lower part of the brain and that can spread to the spine or to other parts of the body. Medulloblastomas are a type of primitive neuroectodermal tumor (PNET).