Which is the most common childhood CNS tumor to metastasize outside brain?
Correct Answer: Medulloblastoma
Description: Glioblastoma, also known as glioblastoma multiforme (GBM), is the most aggressive cancer that begins within the brain. Initially, signs and symptoms of glioblastoma are nonspecific. Uncommon risk factors include genetic disorders, such as neurofibromatosis and Li-Fraumeni syndrome, and previous radiation therapy. Glioblastomas represent 15% of brain tumors. They can either sta from normal brain cells or develop from an existing low-grade astrocytoma. The diagnosis typically is made by a combination of CT scan, MRI scan, and tissue biopsy. No clear way to prevent the disease is known. Typically, treatment involves surgery, after which chemotherapy and radiation therapy are used. The medication temozolomide is used frequently as pa of chemotherapy. High-dose steroids may be used to help reduce swelling and decrease symptoms. Whether trying to remove all or simply most of the cancer is better is unknown. Despite maximum treatment, the cancer usually recurs. The tumor may extend into the meninges or ventricular wall, leading to high protein content in the cerebrospinal fluid (CSF) (> 100 mg/dl), as well as an occasional pleocytosis of 10 to 100 cells, mostly lymphocytes. Malignant cells carried in the CSF may spread (rarely) to the spinal cord or cause meningeal gliomatosis. However, metastasis of GBM beyond the central nervous system is extremely unusual. About 50% of GBMs occupy more than one lobe of a hemisphere or are bilateral. Tumors of this type usually arise from the cerebrum and may exhibit the classic infiltration across the corpus callosum, producing a butterfly (bilateral) glioma. The tumor may take on a variety of appearances, depending on the amount of hemorrhage, necrosis, or its age. A CT scan usually shows an inhomogeneous mass with a hypodense center and a variable ring of enhancement surrounded by edema. Mass effect from the tumor and edema may compress the ventricles and cause hydrocephalus. Ref Harrison20th edition pg 2234 Ref Davidson edition23rd pg 1123
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