Spinal Cord Ependymoma

Ependymomas of the spinal cord are glial tumors arising from ependymal cells along the central canal of the spinal cord. They are rare, typically have a long natural history, and behave differently than their intracranial counterparts. Spinal cord ependymomas often present insidiously with back pain or neurologic deficits that are dependent on their location within the cord. The updated 2021 World Health Organization (WHO) Central Nervous System (CNS) classification categorizes ependymomas of the spinal cord distinctly from supratentorial and infratentorial ependymomas. There are four subtypes of spinal cord ependymoma, including spinal subependymoma (WHO grade 1), myxopapillary ependymoma (MPE; WHO grade 2), spinal ependymoma (WHO grade 2 or 3), and spinal ependymoma MYCN-amplified. MPE tends to occur in the conus medullaris, cauda equina, or filum terminale. They were previously considered WHO grade 1, but are now classified as WHO grade 2 based on their propensity for recurrence. Spinal ependymomas should be imaged with MRI with and without contrast of the entire neuraxis to rule out distant disease. Cytology can be obtained to evaluate for leptomeningeal spread. Treatment of all spinal ependymomas consists of maximal safe surgical resection, with gross total resection (GTR) offering the best chance for long-term control and possible cure, and specifically complete en-bloc resection without capsular violation for MPE. The role of postoperative radiation (RT) is controversial. When implemented, the RT dose is typically 50.4–54 Gy at 1.8 Gy per fraction using highly conformal techniques, such as intensity-modulated radiotherapy (IMRT) or proton therapy. Spinal subependymoma can typically be managed with surgery alone with RT reserved for multiply recurrent or inoperable/unresectable and progressive/symptomatic disease. For MPE following en-bloc GTR, observation is preferred, but adjuvant RT can be employed, whereas following piecemeal or STR, adjuvant RT is preferred. Grade 2 spinal ependymomas that undergo GTR are typically observed, whereas adjuvant RT is preferred following STR. Spinal ependymomas that are grade 3 or MYCN-amplified are rare but are recommended to undergo adjuvant RT regardless of the extent of resection given their aggressive nature. For all spinal cord ependymomas, continued follow-up with MRI with and without contrast is essential, as late recurrences can occur.