The Clinical Features and Surgical Outcomes of Spinal Cord Tanycytic Ependymomas: A Report of 40 Cases

Stretched intradural extramedullary tanycytic ependymoma of the thoracic spine

Background:

Tanycytic ependymoma is a rare variant of ependymoma that commonly affects the cervical and thoracic spinal cord. It usually arises as intramedullary lesions and extramedullary cases are extremely rare.

Case Description:

We present a 77-year-old woman with the complaints of a 2-year history of progressive paraparesis and sensory loss in her lower extremities. Magnetic resonance imaging revealed a stretched and fusiform intradural extramedullary lesion at T5-T10 level. Gross total removal of the tumor was achieved and a definitive diagnosis of tanycytic ependymoma was established.

Conclusion:

This case thus represents a rare case of thoracic intradural extramedullary tanycytic ependymoma and, to the best of our knowledge, it represents the longest intradural extramedullary tanycytic ependymoma in craniocaudal direction ever reported in the literature.

Complete Versus Incomplete Surgical Resection in Intramedullary Ependymomas: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review.

OBJECTIVE

To compare outcomes of complete versus incomplete resection in primary intramedullary spinal cord ependymoma.

METHODS

A comprehensive search of the MEDLINE, CENTRAL, and Embase databases was conducted by 2 independent investigators. Random-effect meta-analysis and meta-regression with seven covariates were performed to evaluate the reason for the heterogeneity among studies. We also used individual patient data in the integrative analysis to compare complete and incomplete resection based on 4 outcomes: progression-free survival (PFS), overall survival (OS), postoperative neurological improvement (PNI), and follow-up neurological improvement (FNI).

RESULTS

A total of 23 studies were identified, including 407 cases. Significant heterogeneity among included studies was observed in risk estimates (I² for PFS, FNI, and PNI were 49.5%, 78.3%, and 87.2%, respectively). The mean follow-up time across cases was 48.6 ± 2.35 months. Cox proportional multivariable analysis revealed that the complete resection can prolong PFS (model, hazard ratio = 0.18, CI 0.05-0.54, P = .004,) and improve the FNI (binary logistic regression, adjusted odds ratio = 16.5, CI 1.6-171, P = .019). However, PNI and OS were similar in patients with incomplete resected spinal cord ependymoma compared with complete resection (binary logistic regression respectively and Cox multivariable analysis, P > .5).

CONCLUSION

The data presented in this study showed that OS was not significantly affected by the degree of surgery. However, complete resection of intramedullary ependymomas provides the optimal outcomes with longer PFS and better long-term neurological outcomes than incomplete resection.

Multisegmental versus monosegmental intramedullary spinal cord ependymomas: perioperative neurological functions and surgical outcomes

Multiple factors, such as tumor size, lateralization, tumor location, accompanying syringomyelia, and regional spinal cord atrophy, may affect the resectability and clinical prognosis of intramedullary spinal cord ependymomas. However, whether long-segmental involvement of the spinal cord may impair functional outcomes remains unclear. This study was aimed to compare perioperative neurological functions and long-term surgical outcomes between multisegmental ependymomas and their monosegmental counterparts. A total of 62 patients with intramedullary spinal cord ependymoma (WHO grade II) were enrolled, and all of them underwent surgical resection. The patients were classified into the multisegmental group (n = 43) and the monosegmental group (n = 19). Perioperative and long-term (average follow-up period, 47.3 ± 21.4 months) neurological functions were evaluated using the modified McCormick (mMC) scale and the modified Japanese Orthopaedic Association (mJOA) scoring system. Preoperative neurological functions in the multisegmental group were significantly worse than those in the monosegmental group (P < 0.05). However, postoperative short-term neurological functions, as well as long-term functional outcomes, were similar between the two groups (P > 0.05). Logistic regression analysis showed that preoperative mMC and mJOA scores were significantly correlated with neurological improvement during the follow-up period (P < 0.05). Multisegmental involvement of the spinal cord is associated with worse neurological functions in patients with intramedullary spinal cord ependymoma, while the long-term prognosis is not affected. The preoperative neurological status of the patient is the only predictor of long-term functional improvement.

Molecular characterization of histopathological ependymoma variants

According to the WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas, and RELA-fusion-positive ependymomas (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e., the clear cell, papillary, and tanycytic ependymoma. In parallel, global DNA methylation patterns distinguish nine molecular groups, some of which tightly overlap with histopathological subgroups. However, the match of the aforementioned histological variants to DNA methylation classes remains unclear. We analyzed histomorphology, clinical parameters, and global DNA methylation of tumors with the initial histological diagnoses of tanycytic (n = 12), clear cell (n = 14), or papillary ependymoma (n = 19). Forty percent of these tumors did not match to the epigenetic profile of ependymomas, using a previously published DNA methylation-based classifier for brain tumors. Instead, they were classified as low-grade glioma (n = 3), plexus tumor (n = 2), CNS high-grade neuroepithelial tumor with MN1 alteration (n = 2), papillary tumor of the pineal region (n = 2), neurocytoma (n = 1), or did not match to any known brain tumor methylation class (n = 8). Overall, integrated diagnosis had to be changed in 35.6% of cases as compared to the initial diagnosis. Among the tumors molecularly classified as ependymoma (27/45 cases), tanycytic ependymomas were mostly located in the spine (5/7 cases) and matched to spinal or myxopapillary ependymoma. 6/8 clear cell ependymomas were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas with a positive ependymoma match (12/19 cases) showed either a "papillary" (n = 5), a "trabecular" (n = 1), or a "pseudo-papillary" (n = 6) growth pattern. The papillary growth pattern was strongly associated with the methylation class B of posterior fossa ependymoma (PFB, 5/5 cases) and tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Tumors with pseudo-papillary histology matched to the methylation class of myxopapillary ependymoma (4/6 cases), whereas the trabecular case was anatomically and molecularly a spinal ependymoma. Our results show that the diagnosis of histological ependymoma variants is challenging and epigenetic profiles may improve diagnostic accuracy of these cases. Whereas clear cell and papillary ependymomas display correlations between localization, histology, and methylation, tanycytic ependymoma does not represent a molecularly distinct subgroup.

Extramedullary tanycytic ependymoma of the lumbar spinal cord

Tanycytic ependymoma is a rare variant of ependymoma that commonly affects the cervical and thoracic spinal cord. It usually arises as intramedullary lesions, and extramedullary cases are extremely rare. We report a case of a 44-year-old woman who was diagnosed with tanycytic ependymoma in her lumbar spine at level 2-3. The tumor mass developed in an intradural extramedullary location. Histopathologically, tanycytic ependymoma can be misdiagnosed as schwannoma or pilocytic astrocytoma. Immunohistochemical findings such as strong positivity for glial fibrillary acidic protein, perinuclear dot-like positive patterns for epithelial membrane antigen, and focal positivity for S100 protein are helpful in diagnosing tanycytic ependymoma. It is important to be aware of this rare tumor to ensure appropriate patient management and accurate prognosis.

Rare Giant Intradural Extramedullary Ependymoma

A 23-year-old female was admitted to our hospital because she had suffered from back pain for 3 years and paralysis of both lower limbs for 10 days. Neurologic examination showed sensory disturbance and complete paralysis in bilateral lower extremities with negative Babinski sign. Contrast-enhanced magnetic resonance imaging showed there was an enhanced intradural lesion between T2 and T12, which pressed the spinal cord. The lesion was resected completely by laminectomy approach, and the tumor was totally intradural extramedullary. Postoperative pathologic findings confirmed that the lesion was ependymoma. Preoperative symptoms recovered slightly after surgery. The back pain disappeared and muscle strength of both lower extremities returned to level 4 one year after the operation. Meanwhile, her sensory function in both legs improved but was not completely normal. Intradural extramedullary primary ependymomas are rare. To our knowledge, this case is the largest one ever reported in the literature.