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Medulloblastoma What is a medulloblastoma? Medulloblastoma is a form of primitive neuroctodermal tumor PNET. Other PNET tumors include retinoblastoma, pineal blastoma, neuroblastoma, esthesioneuroblastoma, ganglioblastoma, ependymoblastoma and polar spongioblastoma. The tumor tends to occur on the roof of the fourth ventricle in a location called the fastigium. Who is most likely to have a medulloblastoma?Medulloblastomas are 15-20% of all pediatric tumors. They occur most frequently in the first decade of life. Boys are twice as likely to get medulloblastomas as girls. What are they symptoms? The symptoms suggestive of a medulloblastoma would be headache and vomiting which are symptoms of increased intracranial pressure. In addition, there may be symptoms of cerebellar dysfunction such as disequilibrium when the patient is seated and discoordination of the extremities. How is it diagnosed? Diagnosis of medulloblastoma is made with a CT scan or preferably and MRI scan. Because medulloblastomas have a tendency to seed, i.e. spread to other parts of the central nervous system, the spine should be imaged with MR scanning as well (or myleography if MR is not available). What is the treatment? The treatment of medulloblastoma is to surgically remove as much as possible without giving the patient a neurologic deficit. Surgery can be followed with radiation, but radiation should be administered with caution because it can cause brain problems for children less than three years old. In addition, radiation should be administered to the spine. If the medulloblastoma recurs chemotherapy (CCNU vincristine) can be administered. Approximately 30-40% of children who have their posterior fossa opened for resection of a medulloblastoma will require a VP shunt to preserve circulation of the cerebrospinal fluid.
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