offers extensive brain tumor information, treatment and research updates, and patient/family storiesMedulloblastoma is a rapidly-growing tumor of the cerebellum — the lower, rear portion of the brain. Also called the “posterior fossa,” this area controls balance, posture, and complex motor functions such as speech and balance. Tumors located in the cerebellum are referred to as “infratentorial” tumors. That means the tumor is
located below the “tentorium,” a thick membrane that separates the larger, cerebral hemispheres of the brain from the cerebellum. In children, medulloblastoma arises most often near the vermis, the narrow worm-like bridge that connects the cerebellum’s two sides. In adults this tumor tends to occur in the body of the cerebellum, especially toward the edges.
Medulloblastoma is the most common of the embryonal tumors — tumors that arise from “embryonal” or “immature” cells at the earliest stage of their development. Other embryonal tumors include histologically similar tumors such as supratentorial primitive neuroectodermal tumors, central neuroblastomas, and ependymoblastomas. These tumors are now known to be molecularly different than medulloblastoma, as are other embryonal tumors such as medulloepithelioma and atypical teratoid/rhabdoid tumors.