Objective: To define the prognostic factors for progression and to determine the impact of the histological grading (according to the World Health Organization) on the progression-free survival (PFS) of filum terminale ependymomas.
Methods: A retrospective chart review of 38 patients with ependymoma of the filum terminale was performed, focusing on demographic data, preoperative symptoms, tumor size, quality of resection, presence of a tumor capsule, and histological grade.
Results: Gross total resection (GTR) was achieved in 30 patients (78.9%). Histopathological analysis found 21 (55.3%) myxopapillary grade I ependymoma (MPE), 16 (42.1%) ependymoma grade II (EGII), and 1 (2.6%) ependymoma grade III. There was no significant difference between the mean±SD volume of MPE (5840.5±5244.2mm3) and the one of EGII (7220.3±6305.9mm3, p=0.5). The mean±SD follow-up was 54.1±38.4 months. At last follow-up, 30 (78.9%) patients were free of progression. In multivariate analysis, subtotal resection (p=0.015) and infiltrative tumor (p=0.03) were significantly associated with progression. The PFS was significantly higher in patients with encapsulated tumor than in patients with infiltrative tumor (log-rank p=0.01) and in patients who had a GTR in comparison with those who had an incomplete resection (log-rank p=0.05). There was no difference in PFS between patient with MPE and EGII (p=0.1).
Conclusion: The progression of ependymoma of the filum terminale highly depends on the quality of resection, and whether the tumor is encapsulated. Except for anaplastic grade, histopathological type does not influence progression.
Keywords: Conus medullaris; Ependymoma; Filum terminale; Myxopapillary ependymoma; Prognostic factor; Recurrence.
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