Loading...
Ependymoma: Glioma derived from EPENDYMOGLIAL CELLS that tend to present as malignant intracranial tumors in children and as benign intraspinal neoplasms in adults. It may arise from any level of the ventricular system or central canal of the spinal cord. Intracranial ependymomas most frequently originate in the FOURTH VENTRICLE and histologically are densely cellular tumors which may contain ependymal tubules and perivascular pseudorosettes. Spinal ependymomas are usually benign papillary or myxopapillary tumors. (From DeVita et al., Principles and Practice of Oncology, 5th ed, p2018; Escourolle et al., Manual of Basic Neuropathology, 2nd ed, pp28-9)Infratentorial Neoplasms: Intracranial tumors originating in the region of the brain inferior to the tentorium cerebelli, which contains the cerebellum, fourth ventricle, cerebellopontine angle, brain stem, and related structures. Primary tumors of this region are more frequent in children, and may present with ATAXIA; CRANIAL NERVE DISEASES; vomiting; HEADACHE; HYDROCEPHALUS; or other signs of neurologic dysfunction. Relatively frequent histologic subtypes include TERATOMA; MEDULLOBLASTOMA; GLIOBLASTOMA; ASTROCYTOMA; EPENDYMOMA; CRANIOPHARYNGIOMA; and choroid plexus papilloma (PAPILLOMA, CHOROID PLEXUS).Spinal Cord Neoplasms: Benign and malignant neoplasms which occur within the substance of the spinal cord (intramedullary neoplasms) or in the space between the dura and spinal cord (intradural extramedullary neoplasms). The majority of intramedullary spinal tumors are primary CNS neoplasms including ASTROCYTOMA; EPENDYMOMA; and LIPOMA. Intramedullary neoplasms are often associated with SYRINGOMYELIA. The most frequent histologic types of intradural-extramedullary tumors are MENINGIOMA and NEUROFIBROMA.Supratentorial Neoplasms: Primary and metastatic (secondary) tumors of the brain located above the tentorium cerebelli, a fold of dura mater separating the CEREBELLUM and BRAIN STEM from the cerebral hemispheres and DIENCEPHALON (i.e., THALAMUS and HYPOTHALAMUS and related structures). In adults, primary neoplasms tend to arise in the supratentorial compartment, whereas in children they occur more frequently in the infratentorial space. Clinical manifestations vary with the location of the lesion, but SEIZURES; APHASIA; HEMIANOPSIA; hemiparesis; and sensory deficits are relatively common features. Metastatic supratentorial neoplasms are frequently multiple at the time of presentation.Brain Neoplasms: Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.Cerebral Ventricle Neoplasms: Neoplasms located in the brain ventricles, including the two lateral, the third, and the fourth ventricle. Ventricular tumors may be primary (e.g., CHOROID PLEXUS NEOPLASMS and GLIOMA, SUBEPENDYMAL), metastasize from distant organs, or occur as extensions of locally invasive tumors from adjacent brain structures.Central Nervous System Neoplasms: Benign and malignant neoplastic processes that arise from or secondarily involve the brain, spinal cord, or meninges.Cauda Equina: The lower part of the SPINAL CORD consisting of the lumbar, sacral, and coccygeal nerve roots.Siderosis: A form of pneumoconiosis resulting from inhalation of iron in the mining dust or welding fumes.Sacrococcygeal Region: The body region between (and flanking) the SACRUM and COCCYX.Neurosurgical Procedures: Surgery performed on the nervous system or its parts.Radiotherapy, Conformal: Radiotherapy where there is improved dose homogeneity within the tumor and reduced dosage to uninvolved structures. The precise shaping of dose distribution is achieved via the use of computer-controlled multileaf collimators.Medulloblastoma: A malignant neoplasm that may be classified either as a glioma or as a primitive neuroectodermal tumor of childhood (see NEUROECTODERMAL TUMOR, PRIMITIVE). The tumor occurs most frequently in the first decade of life with the most typical location being the cerebellar vermis. Histologic features include a high degree of cellularity, frequent mitotic figures, and a tendency for the cells to organize into sheets or form rosettes. Medulloblastoma have a high propensity to spread throughout the craniospinal intradural axis. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2060-1)Fourth Ventricle: An irregularly shaped cavity in the RHOMBENCEPHALON, located between the MEDULLA OBLONGATA; the PONS; and the isthmus in front, and the CEREBELLUM behind. It is continuous with the central canal of the cord below and with the CEREBRAL AQUEDUCT above, and through its lateral and median apertures it communicates with the SUBARACHNOID SPACE.Glioma, Subependymal: Rare, slow-growing, benign intraventricular tumors, often asymptomatic and discovered incidentally. The tumors are classified histologically as ependymomas and demonstrate a proliferation of subependymal fibrillary astrocytes among the ependymal tumor cells. (From Clin Neurol Neurosurg 1997 Feb;99(1):17-22)