What rae general remarks regarding NCS tumors?

➢The annual incidence of CNS tumors ranges from 10 to 17 per 100,000 Individuals for intracranial tumors ➢ Tumors of the CNS account for as many of 20% of all pediatric tumors. ➢Childhood CNS tumors differ from those in adults in both histologic subtype and location ( In childhood: tumors are likely to arise in the posterior fossa, whereas tumors in adults are mostly supratentorial). ➢Tumors of the nervous system have unique characteristics that set them apart from neoplastic processes elsewhere in the body. • They do not have morphologically evident premalignant or in situ stages comparable to those of carcinomas. • Even low-grade lesions may infiltrate large regions of the brain, leading to serious clinical deficits, inability to be resected, and poor prognosis. • The anatomic site of the neoplasm can influence outcome independent of histologic classification due to local effects • Even the most highly malignant gliomas rarely spread outside of the CNS.