Intracranial ependymoma

Intracranial ependymoma, are believed to arise from trapping of embryonic rests of ependymal tissue in the developing brain parenchyma ¹⁾.

They constitute 2 to 9% of all intracranial tumors and up to 12% of pediatric brain tumors.

It is the third most common intracranial glioma in children.

At least half of ependymomas present in the first two decades of life.

Ependymal tumors in adults are rare, accounting for less than 4 % of primary tumors of the central nervous system in this age group.

The majority of intracranial ependymomas (60%) are located in the posterior fossa (infratentorial), usually arising from the lateral recess of the fourth ventricle (molecular subgroup: Posterior fossa type A Ependymoma) and midline inferior floor of the fourth ventricle near the obex (molecular subgroup: Posterior Fossa B) ^{2) 3) 4) 5)}

The remainder (40%) are located supratentorially and up to half of these are intraparenchymal.

Intracranial ependymoma classification.

Loss of chromosome 22 and gain of 1q are the most frequent genomic aberrations in ependymomas, indicating that genes mapping to these regions are critical in their pathogenesis. Using real-time quantitative PCR, Karakoula et al. measured relative copy numbers of 10 genes mapping to 22q12.3-q13.33 and 10 genes at 1q21-32 in a series of 47 pediatric intracranial ependymomas. Loss of one or more of the genes on 22 was detected in 81% of cases, with RAC2 and C22ORF2 at 22q12-q13.1 being deleted most frequently in 38% and 32% of ependymoma samples, respectively. Combined analysis of quantitative-PCR with methylation-specific PCR and bisulphite sequencing revealed a high rate (>60% ependymoma) of transcriptional inactivation of C22ORF2, indicating its potential importance in the development of pediatric ependymomas. Increase of relative copy numbers of at least one gene on 1q were detected in 61% of cases, with TPR at 1q25 displaying relative copy number gains in 38% of cases. Patient age was identified as a significant adverse prognostic factor, as a significantly shorter overall survival time (P = 0.0056) was observed in patients <2 years of age compared with patients who were >2 years of age. Loss of RAC2 at 22q13 or amplification of TPR at 1q25 was significantly associated with shorter overall survival in these younger patients (P = 0.0492 and P = < 0.0001, respectively). This study identifies candidate target genes within 1q and 22q that are potentially important in the pathogenesis of intracranial pediatric ependymomas ⁶⁾.

Intracranial ependymoma clinical features

Intracranial ependymoma diagnosis.

see Intracranial ependymoma treatment.

Intracranial ependymoma outcome.

see Intracranial ependymoma case series.