Intradural extramedullary ventral thoracic spinal ependymoma: illustrative case

Abstract

BACKGROUND

Spinal cord ependymomas are typically intramedullary and rarely present as intradural extramedullary (IDEM) tumors. Here, the authors report a case of a long-segment thoracic IDEM ependymoma that was surgically treated, along with a review of the existing literature on this uncommon presentation.

OBSERVATIONS

A 27-year-old female presented with a 1-year history of low back pain. The condition was initially mild and managed conservatively; however, 6 weeks prior to presentation, she developed progressive weakness in both lower limbs. Spinal MRI revealed a large IDEM mass along the ventral aspect of the thoracolumbar spine. The patient underwent laminoplasty (T9–L1 laminae) and gross-total tumor excision. The procedure was well tolerated, and no postoperative complications were observed. Histopathological examination confirmed the diagnosis of a WHO grade 2 ependymoma. At the 2-year follow-up, the patient had normal neurological function, and MRI revealed no evidence of recurrence.

LESSONS

IDEM exophytic growth of spinal ependymomas is rare but highly surgically treatable. Although the prognosis is favorable following complete excision, careful attention to the adjacent spinal anatomy is essential to minimize the complications. Further studies are needed to evaluate the role of adjuvant therapy.

https://thejns.org/doi/10.3171/CASE26500

Ependymoma is the most common intramedullary spinal tumor in adults. It arises from ependymal cells lining the central canal of the spinal cord and is therefore typically intramedullary, except for tumors located in the filum terminale or the conus medullaris.^1–3 However, it can rarely present as an intradural extramedullary (IDEM) tumor, a phenomenon described only in a limited number of case reports.⁴ Because of the rarity of IDEM ependymomas, their clinical features and optimal management remain poorly understood. Here, we present a case of a long-segment thoracic spine IDEM ependymoma that was surgically treated, along with a review of the existing literature on this uncommon presentation.

Illustrative Case

We present the case of a 27-year-old female housewife and mother of one child with no significant past medical history, who presented with a 1-year history of back pain that began during pregnancy. The pain was initially mild and was managed conservatively with analgesics. However, 6 weeks before presentation to our hospital, she developed progressive weakness in both lower limbs without associated sphincter disturbance. On current presentation, she was alert and ambulated with assistance.

Neurological examination revealed unremarkable cognitive, cranial nerve, and upper extremity function. Motor examination of the lower extremities demonstrated symmetrical weakness of 4/5 in all muscle groups, more marked proximally, with normal symmetric tendon reflexes. The sensory examination was unremarkable. There were no skin stigmata or family history of neurofibromatosis.

MRI of the thoracolumbar spine (Fig. 1) demonstrated a large IDEM mass lesion along the ventral aspect of the spinal cord, extending from T8–9 to L1. The cranial part of the lesion was not clearly separable from the spinal cord, with an associated intramedullary high signal intensity, likely representing edema. The mass was hypointense to the spinal cord on T1-weighted images and hyperintense on T2-weighted images, with multiple intralesional signal voids representing small vessels. Extension to the bilateral neural foramina was observed at the T10–11, T11–12, and T12–L1 levels. In postcontrast images, the mass demonstrated heterogeneous enhancement. Brain and cervical spine MRI findings were unremarkable.

FIG. 1.

Preoperative MR images of the thoracic spine demonstrating a large IDEM mass along the ventral aspect of the spinal cord, causing significant mass effect from T8–9 to L1. The mass appeared isointense on a sagittal T1-weighted image (A) and hyperintense on T2-weighted sagittal (B) and axial (D) images. Postcontrast, it demonstrated heterogeneous enhancement on sagittal (C) and axial (E) images. There was extension to the bilateral neural foramina at T10–11, T11–12, and T12–L1 (E).

This constellation of findings suggests IDEM tumors, such as schwannoma and meningioma, and primary exophytic intramedullary spinal cord neoplasms, such as ependymoma, hemangioblastoma, and astrocytoma, as potential causes.

Surgical planning was performed with the patient positioned on a Jackson table and fluoroscopic localization of the T8–L1 level. Intraoperative monitoring was performed using motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs). The patient underwent multilevel thoracolumbar laminoplasty (T9–L1) with rostrally hinged laminae. Midline durotomy was performed, and the spinal cord was found to be stretched from the ventral mass. Under the microscope, the denticulate ligaments were cut at multiple levels on both sides to allow spinal cord rotation and reflection during tumor resection. The tumor was identified ventral to the spinal cord, encasing, but not infiltrating, the nerve roots. However, at the upper end, there was a ventral attachment to the spinal cord. The tumor was rubbery in consistency and mildly vascularized. Using microsurgical dissection and ultrasonic aspiration, we resected the tumor through working windows created between the nerve roots at multiple spinal levels. Gross-total resection (GTR) was achieved while preserving the spinal nerve roots. There were no changes in SSEP or MEP signals throughout the surgery (Video 1).

VIDEO 1. Intraoperative video demonstrating the miscroscopic surgical technique for gross-total resection of a ventral IMED tumor in T8–9 to L1 region. Click here to view.

The patient tolerated the procedure well and did not experience any worsening of neurological deficits. An immediate postoperative MRI study confirmed complete tumor resection. Postoperatively, the patient had an uneventful recovery and was discharged in good clinical and neurological condition.

Histopathological examination revealed a neoplasm with oval and uniform cell nuclei with a fibrillary background, hypo- and hypercellular areas, perivascular pseudorosettes, and true ependymal rosettes. Focal areas of hemosiderin-laden macrophages and small areas of necrosis were present. Up to 2 mitotic figures per 10 high-power fields were identified. Immunohistochemical analysis revealed diffuse positivity for GFAP and S100, while EMA was negative. The Ki-67 index was up to 10% in hotspot areas. Overall, the findings were most consistent with those of a WHO grade 2 ependymoma (Fig. 2).

FIG. 2.

H&E stains at ×40 (A) and ×100 (B) original magnification, revealing a neoplasm with a fibrillary background, alternating hypocellular and hypercellular areas, perivascular pseudorosettes, and true ependymal rosettes. Immunohistochemical stains for GFAP (C) and S100 (D) showing diffuse positivity, while EMA was negative. Overall, the findings were consistent with those of a WHO grade 2 ependymoma.

The patient had a 2-year follow-up, clinically and radiologically, with resolution of her prior weakness, no evidence of tumor recurrence on her last MRI study, and no adjuvant therapy was advised (Fig. 3).

FIG. 3.

Follow-up MR images obtained at 2 years demonstrating no evidence of recurrent tumors. Sagittal T1-weighted MR image (A) demonstrating flattening of the spinal cord and sagittal (B) and axial (D) T2-weighted images showing stable intramedullary high T2 signal intensity. No abnormal contrast enhancement was observed in the surgical bed along the cord surface or nerve roots on sagittal (C) and axial (E) T1-weighted images postcontrast.

Informed Consent

The necessary informed consent was obtained in this study.

Discussion

Observations

Spinal ependymomas are typically intramedullary tumors that are often benign. Ependymomas are believed to originate from ependymal cells. In the spinal cord, these cells are predominantly located along the central canals. However, some ependymal cells are thought to persist during neural tube closure, potentially giving rise to IDEM ependymomas.¹ Spinal IDEM ependymomas are uncommon entities within the broad spectrum of spinal cord tumors.² These tumors typically arise from ependymal cells and grow through the anterior/anterolateral surface of the spinal cord as an exophytic tumor, expanding in the ventral aspect of the spinal canal adjacent to the dural sac (Fig. 4). They are often misdiagnosed because of their rarity and overlap in clinical features with more common extramedullary pathologies.

FIG. 4.

A: Illustration demonstrating attachment of the tumor to the spinal cord in the current case. B: Postoperative MR image showing the origin of the tumor and exophytic path location.

Our literature search in August 2025 identified 214 articles related to IDEM tumors. After screening for relevance, 90 articles unrelated to spinal ependymoma were excluded, leaving 124 articles for review. Of these, 50 articles describing intramedullary ependymomas were excluded, leaving 74 articles to be reviewed. A further 34 articles were excluded because they lacked specific tumor location details, leaving 40 eligible studies. Among these, 30 articles were excluded because they did not clearly describe the ventral (anterior) location of the tumor. Ultimately, 10 articles met the inclusion criteria, representing reported cases of ventral IDEM spinal ependymomas (Supplemental Fig. 1).^5–14

The literature review summarized in Table 1 describes a synopsis of 10 cases of ventral IDEM spinal ependymomas that have been documented and confirmed through histological examination. Ependymomas are generally more common in women. In a review article, Duffau et al. hypothesized the existence of hormonal components.³ Among the cases presented in our review, including our case, 7 of the 11 patients were female.^5–8,13 The mean age was 40 years (range 17–62 years). The thoracic region of the spinal cord is a common location for IDEM ependymomas, in contrast to intramedullary ependymomas, which are more commonly found in the cervical spinal cord. In this review, IDEM ependymomas were focal WHO grade 2 and located in the thoracic and cervical regions in 3 cases each (Table 1). Multifocal and disseminated tumors are usually WHO grade 3 and were reported in 4 cases involving the cervicomedullary junction, lumbar, sacral, and cauda equina regions, 2 of which had intracranial dissemination.^7,11,13,14 Typical clinical symptoms include slowly progressive myelopathy with pain and motor deficits depending on the tumor location.

TABLE 1.

Review of the literature on ventral IDEM spinal ependymoma

Authors & Year	Age (yrs) & Sex	Location	Surgical Management	Intraop Findings	Pathology	Adjuvant Therapy	Outcome
Wolfla et al., 19975	59, F	Focal, T10–11	Laminectomy, GTR	Circumscribed, encapsulated, pinkish mass, not in continuity w/ the spinal cord, dura, or rootlets	Ependymoma, NOS	None	FU at 6 mos: recovery of neurological deficit; no recurrence
Payer et al., 19996	62, F	Focal, T6–7	Hemilaminectomy & costotransversectomy, GTR	Tumor was yellowish-brown, encapsulated, & well demarcated from the spinal cord & nerve roots laterally & less so medially	Ependymoma, WHO grade 2	None	FU NS: improving Brown-Séquard syndrome below T6
Schuurmans et al., 20067	29, F	Multisegmental focal, C3–6 & L5–S1	Laminectomy, GTR	Tumor appeared to be connected to the cord only at C5	Ependymoma, WHO grade 3	Spinal radiation	FU at 6 mos; improved weakness but w/ residual painful sensations in legs & slight micturition difficulties due to postradiation myelopathy; no spinal recurrent tumor; FU at 2 yrs: developed intracranial recurrence
Fasoli et al., 20088	32, F	Focal, T3–5	Laminectomy, GTR	Well circumscribed, not infiltrating the spinal cord	Ependymoma, NOS	None	FU at 2 yrs: no neurological deficit; no recurrence
Kinsman et al., 20119	53, M	Focal, C5–7	Laminectomy, GTR	Tumor was grossly purplish-brown, exophytic & very closely adherent to the lateral wall of the spinal cord	Ependymoma, WHO grade 3	Spinal radiation	FU NS: recovery of neurological deficit
Ha & Shin, 201210	36, F	Focal, C6–T1	Laminectomy, GTR	Stalk attached the tumor to the C7 spinal nerve root	Ependymoma, WHO grade 2	None	FU at 6 mos: no neurological deficit; no recurrence
Guarnieri et al., 201411	53, M	Multisegmental focal, cervical & thoracic spine	Laminectomy, STR	Tumor was soft, w/ no attachment to the dura or spinal cord; arachnoid infiltration was noted	Ependymoma, WHO grade 2	Chemotherapy (carboplatin)	FU NS: recovery of neurological deficit
Pomeraniec et al., 201512	23, M	Focal, C4–7	Laminoplasty, STR	Tumor was adherent to & partially enveloped the nerve roots, including those at the exiting C6 level	Ependymoma, WHO grade 3	Craniospinal radiation	FU at 1 yr: recovery of neurological deficit; stable residual nodular lesions along the surface of the cervical & thoracic spinal cord
Chakravorty et al., 201713	47, F	Multisegmental focal, S2 & T9; diffuse lesions at the cervicomedullary junction to the lumbar region	Laminectomy, GTR	Soft gray-pink tumor arising from nerve roots	Ependymoma, WHO grade 3	Craniospinal radiation	FU at 4 yrs: recovery of neurological deficit; stable spinal residual lesions
Garg et al., 201914	17, M	Multisegmental diffuse, T6–S2	Laminectomy & aspiration/biopsy	Cystic mass	Ependymoma, WHO grade 2	Radiation & chemo	FU at 12 mos: recovery of neurological deficit; extensive spinal leptomeningeal recurrence & cranial metastasis; craniotomy & biopsy revealed ependymoma, WHO grade 3
Present case	27, F	Multisegemental focal, T9–L1	Laminoplasty, GTR	Tumor exhibited a soft, rubbery consistency, was adherent to the dura, & appeared exophytic w/ adherence to the rt anterior aspect of the spinal cord, w/o involvement of the nerve roots		None	FU at 2 yrs: full recovery of preop neurological deficits; no recurrence

FU = follow-up; NOS = not otherwise specified; NS = not specified; STR = subtotal resection.

On preoperative imaging, differentiating IDEM ependymomas from other IDEM tumors, such as meningiomas or schwannomas, can be challenging. These tumors may appear encapsulated without clear neural or dural attachment or present as dumbbell-shaped lesions extending into the paravertebral region.² This was demonstrated in our case, in which the mass extended into the bilateral neural foramina at multiple locations.

To our knowledge, our case represents another example of a large multisegmental ventral IDEM ependymoma with bilateral neural foraminal extension mimicking a peripheral nerve sheath tumor.¹⁰ Although IDEM ependymomas have been previously described, most reported lesions are focal, spanning one to two spinal segments, and lack foraminal involvement.

This radiographic appearance significantly challenged the preoperative differential diagnosis and surgical planning, highlighting the importance of considering IDEM ependymoma in the differential diagnosis of ventral IDEM lesions with foraminal extension, particularly when imaging characteristics are atypical for more common pathologies such as schwannoma or meningioma.

GTR remains the primary treatment for IDEM ependymomas. Owing to their well-encapsulated nature, these tumors are often amenable to complete resection, which offers the best prognosis for patients with these tumors. However, the ventral location poses significant technical challenges because access requires careful spinal cord mobilization while preserving ventral neurovascular structures and functional nerve roots.

In our literature review, most patients with ventral IDEM ependymomas underwent laminectomy or laminoplasty.^5,7–14 In contrast, hemilaminectomy may be considered in cases in which the tumor is located laterally in the spinal canal.⁶ Most reported IDEM ependymomas were WHO grade 2, which require GTR and follow-up.^{5,6,8,10,11,13} In some cases, they were WHO grade 3 and required adjunctive radiotherapy and/or chemotherapy.^5–10,13 Most patients showed near-complete recovery of neurological deficits.

The present case expands the limited literature on ventral IDEM spinal ependymomas and emphasizes several important clinical considerations for their management. First, these lesions may demonstrate extensive foraminal extension and radiographically mimic more common IDEM tumors, such as schwannomas. Second, despite their benign histological appearance, their ventral location can significantly complicate surgical exposure and safe resection because of their location anterior to the spinal cord and their proximity to neurovascular structures. Finally, awareness of this rare entity may improve preoperative diagnostic accuracy and facilitate surgical planning aimed at maximizing safe GTR while minimizing neurological morbidity.

Lessons

Primary ventral IDEM ependymomas are exceptionally rare lesions that may mimic nerve sheath tumors or meningiomas on preoperative imaging, particularly when associated with extensive foraminal extension. GTR remains the cornerstone of treatment; however, ventral tumor location presents unique microsurgical challenges that require meticulous spinal cord manipulation and preservation of adjacent neurovascular structures to ensure optimal outcomes. This case broadens the spectrum of radiographic presentations reported for IDEM ependymomas and reinforces the importance of considering this diagnosis in atypical ventral IDEM lesions.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Baeesa, Alsindi, Basurrah. Acquisition of data: Baeesa, Alsindi. Analysis and interpretation of data: Baeesa, Alsindi. Drafting the article: Baeesa, Alsindi, Albakri, Basurrah. Critically revising the article: Baeesa, Alsindi, Albakri, Basurrah. Reviewed submitted version of manuscript: Baeesa, Alsindi, Albakri, Basurrah. Approved the final version of the manuscript on behalf of all authors: Baeesa. Administrative/technical/material support: Baeesa, Alsindi, Almansouri. Study supervision: Baeesa, Alsindi, Albakri.

Supplemental Information

Videos

  Video 1. https://vimeo.com/1205498610.

Online-Only Content

Supplementary Materials

  Supplemental Fig. 1. https://thejns.org/doi/suppl/10.3171/CASE26500.

Current Affiliations

Dr. Albakri: Makkah Health Cluster, Makkah, Saudi Arabia.

Correspondence

Saleh S. Baeesa: King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia. sbaeesa@kfshrc.edu.sa; salehbaeesa@gmail.com.