Spinal Cord Ependymoma

Spinal cord ependymoma is a glial tumor of the central canal and the most common intramedullary tumor in adults, accounting for about 60% of adult intramedullary tumors. It arises most often in the cervical and cervicothoracic cord at 30 to 50 years, with a slight male predominance.

Types

• Classic (grade 2): well-circumscribed with a plane of cleavage from cord tissue, so complete removal is often possible
• Myxopapillary (grade 2): conus medullaris and filum terminale, a separate subtype
• Anaplastic (grade 3): uncommon
• MYCN-amplified spinal ependymoma: aggressive, with early spread

NF2 is associated with multiple cervical tumors (loss of merlin on 22q). Syringomyelia is present in 50 to 60% and tumor-related cysts are frequent. Growth is slow, symptoms are present for 1 to 3 years before diagnosis, and after gross total resection 10-year survival is over 90%. Complications: progressive myelopathy, postoperative dorsal column deficit, recurrence and dissemination (myxopapillary and anaplastic types).

• Neck or back pain, often at night, and the most common symptom
• Dysesthesia and sensory loss (dissociated pattern), clumsy hands, progressive limb weakness, gait ataxia
• Sphincter dysfunction in late disease
• Myxopapillary tumors: low back pain, sciatica and cauda equina features
• Red flags: rapid weakness, loss of bladder control, acute worsening from hemorrhage

1. MRI whole spine with gadolinium: a central, symmetric fusiform expansion of the cord, isointense or hypointense on T1, hyperintense on T2, with enhancement, a hemosiderin "cap sign" at the poles, and syringomyelia.
2. MRI brain in suspected NF2, and NF2 gene testing when multiple.
3. Histology: perivascular pseudorosettes, GFAP and EMA positivity, and molecular profiling (MYCN status).
4. CSF cytology only for suspected dissemination.

Differentials: astrocytoma (eccentric, infiltrative), hemangioblastoma, cavernous malformation, demyelinating lesion, syrinx of other cause.

• Surgery is the primary treatment: microsurgical midline myelotomy with intraoperative neurophysiological monitoring (motor and somatosensory evoked potentials) and en bloc removal along the cleavage plane. Gross total resection is achieved in about 80 to 90%.
• Medical: dexamethasone 4 mg IV every 6 hours when there is cord edema (a 10 mg IV load for rapid deficit), tapered after surgery. Omeprazole 20 mg orally daily. Gabapentin 300 mg orally at night, increased by 300 mg every 3 days to 900 to 1800 mg a day in 3 divided doses (reduce in renal impairment) for neuropathic pain.
• Prophylaxis: cefazolin 2 g IV before incision, and enoxaparin 40 mg SC daily from 24 hours after surgery until mobile.
• Radiotherapy for subtotal resection, grade 3 histology and recurrence: 50.4 Gy in 28 fractions of 1.8 Gy. For disseminated myxopapillary or anaplastic disease use craniospinal irradiation 36 Gy then a boost to bulky deposits to 45 to 50.4 Gy.
• Myxopapillary tumors: en bloc resection without opening the capsule to prevent seeding.
• NF2-related tumors: observe asymptomatic lesions, operate for progression, and consider bevacizumab 7.5 mg/kg IV every 3 weeks for progressive disease (monitor blood pressure and proteinuria).
• Rehabilitation: early physiotherapy and occupational therapy, since many patients lose proprioception temporarily.

Follow-up: MRI at 3 months, then every 6 to 12 months for 5 years, then yearly. Counsel on recurrence risk and on a gradual recovery over 6 to 12 months.