1. PRIMARY INTRACRANIAL TUMORS
ESSENTIALS OF DIAGNOSIS
Generalized or focal disturbance of cerebral function, or both.
Increased intracranial pressure in some patients.
Neuroradiologic evidence of space-occupying lesion.
Roughly one-third of all primary intracranial neoplasms (Table 24–4) are meningiomas, one-quarter are gliomas, and the remainder are pituitary adenomas (see Chapter 26), neurofibromas, and other tumors. Certain tumors, especially neurofibromas, hemangioblastomas, and retinoblastomas, may have a familial basis, and congenital factors bear on the development of craniopharyngiomas. Tumors may occur at any age, but certain gliomas show particular age predilections.
Table 24–4.Primary intracranial tumors (listed by major histology grouping and by incidence within each group). ||Download (.pdf) Table 24–4. Primary intracranial tumors (listed by major histology grouping and by incidence within each group).
|Tumor ||Clinical Features ||Treatment and Prognosis |
|Tumors of Meninges |
|Meningioma ||Originates from the dura mater or arachnoid; compresses rather than invades adjacent neural structures. Increasingly common with advancing age. Tumor size varies greatly. Symptoms vary with tumor site—eg, unilateral proptosis (sphenoidal ridge); anosmia and optic nerve compression (olfactory groove). Tumor is usually benign and readily detected by CT scanning; may lead to calcification and bone erosion visible on plain radiographs of skull. ||Treatment is surgical. Tumor may recur if removal is incomplete. |
|Tumors of Neuroepithelial Origin |
|Glioblastoma multiforme ||Presents commonly with nonspecific complaints and increased intracranial pressure. As it grows, focal deficits develop. O6-methylguanine-DNA methyltransferase promoter methylation positivity (seen in 40% of cases) and isocitrate dehydrogenase 1/2 mutations (seen in 10% of cases) carry better prognosis. ||Course is rapidly progressive, with poor prognosis (< 20% survival at 2 years). Total surgical removal is usually not possible. Radiation therapy and temozolamide may prolong survival. Tumor treatment fields added to temozolamide after completion of radiation therapy prolong survival. |
|Astrocytoma ||Presentation similar to glioblastoma multiforme but course more protracted, often over several years. Cerebellar astrocytoma may have a more benign course. Isocitrate dehydrogenase 1/2 mutations (seen in a majority of cases) carry better prognosis in grade II and III tumors. ||Prognosis is variable. By the time of diagnosis, total excision is usually impossible; tumor may be radiosensitive and temozolamide is also helpful in grade II and III tumors. In cerebellar astrocytoma, total surgical removal is often possible. |
|Ependymoma ||Glioma arising from the ependyma of a ventricle, especially the fourth ventricle; leads to early signs of increased intracranial pressure. Arises also from central canal of cord. ||Tumor is best treated surgically if possible. Radiation therapy may be used for residual tumor. |
|Oligodendroglioma ||Slow-growing. Usually arises in cerebral hemisphere in adults. Calcification may be visible on skull radiograph. Co-deletion of 1p/19q and isocitrate dehydrogenase 1/2 mutation required for diagnosis. ||Treatment is surgical and usually successful. Radiation and chemotherapy (temozolamide or procarbazine, lomustine, and vincristine) are used in grade II and III tumors. |
|Brainstem glioma ||Presents during childhood with cranial nerve palsies ...|