Surgical treatment of myxopapillary ependymoma: an institutional case series of 56 patients.

Abstract

The aim of this study was to review the management and outcomes of a consecutive cohort of patients with spinal myxopapillary ependymoma (MPE) treated at the authors' institution over a 23-year period. A retrospective review of all patients treated surgically for spinal MPEs at a single institution between May 1998 and August 2021 was performed. Preoperative and postoperative clinical data, imaging, and/or radiology reports were reviewed to identify patient presentation and outcomes as well as tumor size, location, CSF dissemination, and other features. Method and extent of resection were characterized and related to preoperative tumor characteristics and outcomes. Fifty-six patients underwent 60 index surgical procedures at a single institution, including 4 surgeries for resection of a solitary drop sacral metastasis. The median postoperative follow-up was 126 months (range 22-304 months). En bloc gross-total resection (EGTR) was performed in 15 cases, marginal GTR (MGTR) in 17, piecemeal GTR (PGTR) in 6, piecemeal near-total resection (PNTR) in 9, and subtotal resection (STR) in 13 cases. Of the 55 primary filum terminale MPEs, 40 (73%) arose proximally, with their inferior tumor margin located at or above the L3 vertebral body. Nearly all patients who underwent EGTR (14/15) or MGTR (17/17) had MPEs that originated in the proximal filum terminale. In contrast, 10 of 13 patients who underwent STR had a distal MPE origin (below L3). CSF tumor dissemination, including drop metastases, was identified in 19.6% (11/56) of patients. Tumor size, especially width, significantly influenced the method of complete resection: the mean width of tumors resected with EGTR was 1.0 cm (range 0.4-1.7 cm) while the mean width of MGTR tumors was 1.5 cm (range 1.0-2.2 cm) (p < 0.001). Location, size, and marginal integrity of the tumor surface were important factors that influenced extent and quality of resection. MPEs are benign tumors that arise predominantly from the filum terminale. Resection can be curative, especially for well-marginated tumors arising from the proximal filum terminale. Despite their benign nature, the tumors' lack of a capsule, friable tumor consistency, and frequent direct contact with the CSF and cauda equina create a propensity for local recurrence and CSF dissemination, especially for larger and distally originating tumors. Thus, long-term follow-up is recommended for all patients as is early surgical intervention for small, incidental MPEs.