Tumors of the central nervous system

Primary malignancies of the central nervous system (CNS) are the second most common malignancy during childhood. Data suggest that over 3,000 children under 20 years of age are diagnosed with a brain or spinal cord tumor annually in the United States. These tumors account for the majority of cancer-related deaths in children. The age of peak incidence varies with the histological type of CNS tumor. The presenting signs and symptoms also vary by age as well as by tumor location. Tumor location is an important prognostic factor as the extent of tumor resection has been associated with outcome for many histological types. Tumors of glial origin constitute approximately 50 % of all primary CNS tumors in children, and are grouped into low and high grade gliomas based on their histopathology. Low grade gliomas are a heterogeneous group of tumors with long-term survival rates exceeding 80 % with appropriate treatment. Prognosis for high grade gliomas is much more discouraging. Examples of other CNS tumors include medulloblastomas which occur predominantly in the cerebellum and are the most common malignant CNS tumor in children. Long-term prognosis has improved dramatically for medulloblastoma with 5-year survival rates between 50 % and 80 %. Ependymomas are the third most common pediatric brain tumor. Survival rates in excess of 80 % are being reported for these tumors when gross total tumor resection is attained in conjunction with well designed three dimensional conformal radiation. Craniopharyngiomas represent a benign intracranial tumor with a high survival rate. However, craniopharyngiomas are associated with significant morbidity due to their proximity to the optic nerves and the hypothalamus. Although this chapter is focused primarily on intracranial tumors, acute spinal cord dysfunction from metastatic cord compression is a neurological emergency. Treatment requires timely recognition and prompt intervention as prognosis is most related to the degree of disability at diagnosis.