Giant nondural-based cauda equina meningioma with multiple cysts

Area of Science:

• Neurosurgery
• Oncology
• Pathology

Background:

• Spinal meningiomas typically arise from the dura mater, most commonly in the thoracic or cervical regions.
• Nondural-based meningiomas are exceptionally rare, with only six previously reported cases, all located in the cauda equina region.
• These rare tumors predominantly affect younger females compared to typical intraspinal meningiomas.

Observation:

• A 46-year-old woman presented with a 4-year history of lower back and right leg pain, progressing to bilateral lower extremity weakness.
• Magnetic resonance imaging revealed a giant cauda equina tumor with multiple cysts spanning from T(12) to L(4).
• Surgical exploration identified the tumor loosely draped around cauda equina roots, attached to a rootlet without dural attachment.

Findings:

• Complete tumor removal was achieved via laminectomies and microdissection, involving the sacrifice of an involved cauda equina rootlet.
• Initial intraoperative appearance suggested a neurilemmoma, but histological and immunohistochemical analyses confirmed it as a meningioma.
• This case represents a giant, cystic, nondural-based cauda equina meningioma, a unique presentation within this rare tumor category.

Implications:

• Nondural-based cauda equina meningiomas appear to have specific age and sex predilections, predominantly affecting younger females.
• Accurate preoperative and operative diagnosis of these rare tumors can be challenging.
• Clinical vigilance is crucial when managing cauda equina tumors that mimic neurilemmomas, as they may represent meningiomas, especially in younger female patients.