title: Identification of relevant prognostic histopathologic features in 69 intracranial ependymomas, excluding myxopapillary ependymomas and subependymomas.
abstract: BACKGROUND
  The results of attempts to identify histopathologic parameters that contribute to the clinical outcome of patients with ependymomas have been controversial. This may be due to the relative rareness of ependymomas. Furthermore, in many investigations, myxopapillary ependymomas and subependymomas were included and may have confounded results, because those tumors should be considered clinicopathologic entities distinct from the other ependymomas.
  
  
  METHODS
  In this retrospective study, the influence of the histologic subtype of ependymoma and of individual histologic features on the outcome of 69 patients with ependymomas was investigated. Myxopapillary ependymomas, subependymomas, and ependymomas with spinal localizations were excluded from the analysis. The ependymomas were subdivided into cellular, papillary, clear cell, and tanycytic subtypes. The study extended over a period of 30 years.
  
  
  RESULTS
  No differences in clinical outcome between the four histologic subtypes of ependymomas were revealed. Neither tumor localization (either infratentorial or supratentorial), patient age, nor gender affected survival. The survival of patients who underwent complete tumor resection differed significantly from that of patients who underwent partial resection. In univariate analysis, the features of nuclear atypia, the mitotic index, and the MIB-1 labeling index (LI) significantly influenced survival. With regard to survival, the presence of microcysts, blood vessel density, and the feature of vascular hyalinization demonstrated a trend but did not reach significance. In multivariate analysis, only the mitotic index and the MIB-1 LI were identified as factors with independent prognostic significance (P = 0.027 and P = 0.023, respectively). Both proliferation indices were correlated strongly with each other.
  
  
  CONCLUSIONS
  The results of the univariate analysis indicated that, for patients with intracranial ependymoma, nuclear atypia, the mitotic index, and the MIB-1 LI significantly influenced survival. In the multivariate analysis, the mitotic index and the MIB-1 LI were the only features that had independent prognostic significance. Because both showed strong correlations, only one of them should be included in a grading scheme for intracranial ependymomas.
authors.affiliation: Department of Neurosurgery, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Erkan
authors.initials: E
authors.lastname: Kurt
authors.forename: Ping-Pin
authors.initials: PP
authors.lastname: Zheng
authors.forename: Wim C J
authors.initials: WC
authors.lastname: Hop
authors.forename: Marcel
authors.initials: M
authors.lastname: van der Weiden
authors.forename: Meike
authors.initials: M
authors.lastname: Bol
authors.forename: Martin J
authors.initials: MJ
authors.lastname: van den Bent
authors.forename: Cees J J
authors.initials: CJ
authors.lastname: Avezaat
authors.forename: Johan M
authors.initials: JM
authors.lastname: Kros
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001932:Brain Neoplasms / Q000276:immunology / Q000401:mortality* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000276:immunology / Q000401:mortality* / Q000473:pathology*; D005260:Female; D018315:Glioma, Subependymal / Q000276:immunology / Q000401:mortality* / Q000473:pathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D017730:Ki-1 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011379:Prognosis
chemical_list: D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D017730:Ki-1 Antigen; C440408:MIB-1 antibody