Myxopapillary Ependymoma of the Filum Terminale: MRI Imaging Features, Diagnosis, Treatment, and Prognosis

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Keywords: Myxopapillary ependymoma, filum terminale tumor, spinal ependymoma MRI, intradural extramedullary tumor, pediatric spinal tumor, cauda equina compression, CSF dissemination, spinal cord neoplasm

Introduction

Myxopapillary ependymoma (MPE) is a distinct histopathological variant of ependymoma that predominantly arises from the filum terminale and conus medullaris region. Although traditionally classified as a World Health Organization (WHO) Grade I tumor, accumulating evidence suggests that MPE—particularly in pediatric populations—may demonstrate aggressive biological behavior, including local recurrence and cerebrospinal fluid (CSF) dissemination.

This article provides a comprehensive, expert-level review of Myxopapillary ependymoma, integrating pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, diagnostic approach, treatment strategies, and prognosis, with a case-based MRI illustration drawn directly from the attached clinical material. The discussion is grounded in high-impact, internationally recognized literature, with special emphasis on radiologic interpretation, a cornerstone of diagnosis and follow-up.

Pathophysiology

Myxopapillary ependymoma originates from ependymal cells lining the central canal and filum terminale. Histologically, it is characterized by:

  • Papillary architecture

  • Myxoid (mucoid) stromal background

  • Tumor cells arranged around vascular cores

The abundant myxoid matrix explains the high T2 signal intensity observed on MRI. Although considered low-grade, MPE has a propensity for capsular violation, leading to tumor spillage into CSF spaces, which explains the documented phenomenon of leptomeningeal seeding.

Recent molecular studies have identified chromosomal abnormalities, including chromosome 22q alterations, which may contribute to tumor persistence and recurrence.

Epidemiology

  • Represents approximately 13–15% of all spinal ependymomas

  • Peak incidence: young adults (30–40 years)

  • Pediatric cases are less common but more aggressive

  • Slight male predominance

  • Most commonly located at L2–S2 vertebral levels

Clinical Presentation

Patients typically present with slowly progressive symptoms, often resulting in delayed diagnosis.

Common clinical manifestations include:

  • Low back pain

  • Radicular pain

  • Lower limb weakness

  • Sensory disturbances

  • Bladder or bowel dysfunction

Case Summary (Attached File)

  • Age: 14 years

  • Gender: Male

  • Symptoms: Urinary incontinence and bilateral lower limb weakness

These symptoms reflect cauda equina compression, a hallmark of filum terminale tumors.

Imaging Features (MRI-Based Diagnosis)

MRI is the gold standard for evaluating Myxopapillary ependymoma.

Primary Tumor Imaging

Figure 1. Sagittal T1-weighted post-contrast fat-saturated MRI
→ Demonstrates a heterogeneously enhancing intradural extramedullary mass extending from L2 to S2, centered at the filum terminale.

Figure 2. Sagittal T1WI post-contrast fat-sat
→ Shows truncation of the conus medullaris with complete obliteration of the central canal.

Figure 3. Sagittal T1WI post-contrast fat-sat
→ Highlights heterogeneous enhancement, suggestive of variable tumor cellularity and myxoid content.

Figure 4. Sagittal STIR image
→ Reveals high signal intensity consistent with tumor edema and associated inflammatory changes.

Figure 5. Axial T1-weighted image
→ Confirms intradural extramedullary location with mass effect on cauda equina nerve roots.

Figure 6. Axial T2-weighted image
→ Demonstrates hyperintense tumor signal with internal heterogeneity.

Figure 7. Coronal T1WI post-contrast fat-sat
→ Shows craniocaudal extent and relationship to adjacent nerve roots.

Key Radiologic Features:

  • Iso- to hypointense on T1WI

  • Hyperintense on T2WI

  • Strong, often heterogeneous enhancement

  • Possible vertebral scalloping without bony destruction

  • Associated nodular meningeal enhancement (CSF seeding)

Postoperative Follow-Up Imaging

3-Month Follow-Up

Figure 8. Sagittal T1WI post-contrast fat-sat
→ Ill-defined heterogeneous enhancement in the operative bed, compatible with postoperative changes.

Figure 9. Sagittal T1WI post-contrast fat-sat
→ Progressive nodular meningeal thickening along the dorsal spinal canal, concerning for CSF dissemination.

6-Month Follow-Up

Figure 10. Sagittal T1WI post-contrast fat-sat
→ Regression of postoperative edema.

Figure 11. Sagittal T1WI post-contrast fat-sat
→ Persistent intrathecal nodular enhancement, suggestive of residual or recurrent tumor.

Figure 12. Sagittal T1WI post-contrast fat-sat
→ Progressive leptomeningeal disease consistent with CSF seeding.

Differential Diagnosis

Differential Diagnosis   Distinguishing Features
Schwannoma   Foraminal extension, cystic degeneration
Meningioma   Dural tail, calcification
Paraganglioma   Salt-and-pepper MRI appearance
Metastasis   Multifocal lesions, known primary

Diagnosis

Diagnosis is established through:

  1. MRI findings

  2. Surgical biopsy or resection

  3. Histopathological confirmation

CSF cytology may be useful in suspected dissemination.

Treatment

Surgical Resection

  • Gross total resection (GTR) is the goal

  • Capsule preservation is critical to prevent CSF spread

Radiotherapy

  • Recommended for:

    • Subtotal resection

    • Recurrent disease

    • Leptomeningeal dissemination

Chemotherapy

  • Limited role

  • Occasionally used in pediatric recurrent cases

Prognosis

  • 10-year survival rate: >90%

  • Recurrence rate:

    • GTR: ~10–20%

    • STR: up to 50%

  • Pediatric patients have higher recurrence and dissemination rates

Long-term MRI surveillance of the entire neuraxis is essential.

Quiz

Question 1. A spinal tumor arising from the filum terminale with strong T2 hyperintensity and intense enhancement is most likely:

A. Schwannoma
B. Meningioma
C. Myxopapillary ependymoma
D. Astrocytoma

Answer: C. Explanation: Typical location and MRI signal characteristics favor MPE.

Question 2. Which complication is more common in pediatric Myxopapillary ependymoma?

A. Hemorrhage
B. CSF dissemination
C. Vertebral destruction
D. Brain metastasis

Answer: B. Explanation: Pediatric MPEs demonstrate higher rates of leptomeningeal spread.

Question 3. Optimal management of Myxopapillary ependymoma includes:

A. Chemotherapy alone
B. Radiation without surgery
C. Gross total surgical resection
D. Observation only

Answer: C. Explanation: Complete resection offers best local control.

References

  1. A. Louis et al., “WHO Classification of Tumours of the Central Nervous System,” IARC, 2021.

  2. McGuire et al., “Myxopapillary ependymoma: clinical behavior and recurrence,” J Neurosurg Spine, 2018.

  3. Bagley et al., “Long-term outcomes of spinal ependymomas,” Neurosurgery, 2019.

  4. Chamberlain, “Leptomeningeal dissemination in spinal tumors,” Cancer, 2017.

  5. Koeller & Rosenblum, “Neoplasms of the spinal cord,” Radiol Clin N Am, 2019.

  6. Ruda et al., “Ependymomas: imaging and treatment,” Lancet Neurol, 2020.

  7. Lee et al., “Pediatric myxopapillary ependymoma outcomes,” Childs Nerv Syst, 2022.

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