Spinal Meningioma

Spinal meningioma is a dural-based tumor of arachnoid cap cells within the spinal canal. It makes up 25 to 45% of primary spinal tumors. Most arise in the thoracic spine (about 80%), then the cervical region and rarely the lumbar canal, and 90% are intradural extramedullary. Women are affected in 75 to 85% of cases, typically at 40 to 70 years, which reflects hormone receptor expression (progesterone receptors in most). Multiple tumors suggest NF2.

Most are grade 1, with grade 2 and 3 tumors uncommon. Subtypes include psammomatous (calcified), meningothelial, and clear cell (grade 2, common in children and young adults, and aggressive). Recurrence after complete excision is about 5 to 10% and higher for atypical histology and en plaque growth. Complications: progressive myelopathy with spastic paraparesis, sphincter dysfunction, CSF leak after surgery, and spinal instability after extensive laminectomy.

• Localized or radicular back pain, often worse at night or lying flat
• Gait disturbance, leg stiffness, sensory level, Brown-Sequard pattern and sphincter disturbance
• Slow progression over months to years
• Red flags: rapid deterioration, acute urinary retention, severe bilateral weakness

1. MRI spine with gadolinium: a well-circumscribed, broad dural-based mass, isointense on T1 and T2, with homogeneous avid enhancement, a dural tail, and displacement of the cord.
2. CT: calcification in about 10 to 15% and hyperostosis.
3. Histology after surgery, with grade and progesterone receptor status.
4. MRI brain and NF2 testing when young or multiple.

Differentials: nerve sheath tumor (neurofibroma and schwannoma), metastasis, lymphoma, ependymoma, epidural abscess, disc herniation.

• Surgery for symptomatic tumors: laminectomy or laminoplasty, microsurgical excision with devascularization of the dural origin, and coagulation or resection of the dural attachment with watertight closure (dural graft when excised). Use intraoperative neurophysiological monitoring. Ventral tumors need a lateral or posterolateral approach. Neurological improvement in 80 to 90%.
• Peri-operative: dexamethasone 4 mg IV every 6 hours for edema or progressive deficit (a 10 mg load), omeprazole 20 mg orally daily, cefazolin 2 g IV before incision (3 g if over 120 kg), and enoxaparin 40 mg SC daily once mobile.
• CSF leak: bed rest flat for 24 to 48 hours, lumbar drain 10 mL/h for 3 to 5 days, and re-exploration for persistent leak.
• Asymptomatic or elderly patients with small tumors: observation with MRI at 6 months then yearly.
• Radiotherapy for grade 2 and 3 tumors and for symptomatic residual or recurrent tumors: 50.4 to 54 Gy in 28 to 30 fractions. Stereotactic body radiotherapy (12 to 16 Gy in 1 fraction or 24 Gy in 3 fractions) for inoperable or recurrent lesions.
• Instrumentation for instability from extensive resection.

Follow-up: MRI at 3 months, 1 year and then every 1 to 2 years to year 5 (yearly for atypical tumors). Counsel on recurrence risk and the need for rehabilitation.