A genetic aberration in which the RELA gene becomes fused to an open reading frame of chromosome 11 (RELA-fusion positive) occurs in the majority of supratentorial tumors in children.
The symptomatology depends on the location of the neoplasm. The clinical manifestations of fourth ventricular tumors are described further on; the point to be made here is the frequent occurrence of hydrocephalus and signs of raised intracranial pressure (manifest in children by lethargy, nausea, vomiting, and papilledema). Cerebral ependymomas otherwise resemble the other gliomas in their clinical expression in that seizures occur in approximately one-third of the cases.
The imaging characteristics are rather different from those of other tumors. With CT one observes a well-demarcated heterogeneous hyperdense mass with fairly uniform contrast enhancement. Calcification and some degree of cystic change are common in supratentorial tumors, but less so in infratentorial ones. There are mixed signal characteristics on MRI, generally hypointense on T1 sequences and hyperintense on T2. An intraventricular location supports the diagnosis of ependymoma, but meningioma and a number of other tumors may be found in this location. In keeping with the variability of anaplasia, the interval between the first symptom and the diagnosis ranges from 4 weeks in the most malignant types, to 7 to 8 years.
Treatment and outcome In a follow-up study of 101 cases in Norway, where ependymomas made up 1.2 percent of all primary intracranial tumors (and 32 percent of intraspinal tumors), the postoperative survival was poor. Within a year, 47 percent of the patients had died, although 13 percent were alive after 10 years. Doubtless the prognosis depends on the degree of anaplasia (Mørk and Løken), the location of the tumor, and whether it is operable but the lack of certainty of these dicta have been alluded to earlier. Surgical removal is supplemented by radiation therapy, particularly to address the high rate of seeding of the ventricles and spinal axis. In the treatment of anaplastic ependymomas, antineoplastic drugs are often used in combination with radiation therapy.
This tumor, first illustrated by Matthew Bailie in his Morbid Anatomy (1787) and first identified properly by Bright, in 1831, originates from the dura mater or arachnoid. It was analyzed from every point of view by Harvey Cushing and was the subject of one of his most important monographs (Cushing, 1962). The tumor is discussed again further on in relation to particular sites of origin.
Meningiomas represent approximately one-third of all primary intracranial tumors; they are more common in women than in men (2:1) and have their highest incidence in the sixth and seventh decades of life. Some are familial. There is evidence that persons who have undergone radiation therapy to the scalp or cranium are vulnerable to the development of meningiomas and that the tumors appear at an earlier age in such individuals (Rubinstein et al). Radiofrequency energy exposure from portable cellular devices has failed to be linked to elevated incidence of meningiomas (or gliomas). There are also a number of reports of a meningioma developing at the site of previous trauma, such as a cranial fracture line, but the association is uncertain.