Meningiomas, Schwann-cell and pituitary tumors and metastasis form outside the brain common in adults, are rare in children. Fifty percent of brain tumors in children older than one year develop infratentorially. The traditional practice of classifying CNS tumors on the basis of location is being reevaluated. An international panel of neuropathologist has proposed a revision of the World Health Organization classification system to classify tumors on the basis of histopathologic features alone. Although older children are more likely than infants to have localizing neurologic findings, these are by no means uniformly present.
Many children have recurrent bouts of headache, nausea and vomiting without focal deficits.
These symptoms suggest the presence of increased intracraneal pressure and are particularly common with tumors of the posterior fossa, and pineal region . The headaches increase in frequency, are more severe in the morning, and are typically followed by vomiting. Children who report an unchanging pattern of headaches without focal neurologic findings for more than 12 months have a low probability of CNS tumors. Specific neurologic symptoms, such as ataxia, somnolence, hemiparesis, seizures, head tilt, cranial nerve palsies, diencephalic syndrome, and diabetes insipidus, may occur later in the illness and may suggest localization of the CNS tumor. The unenhanced CT scan can suggest whether a lesion is cystic or solid and whether there are calcifications, hemorrhage, edema, and hydrocephalus.