Clear cell meningioma of the lower lumbar spine without dural attachment: A case report

Clear cell meningioma (CCM) is a rare and aggressive subtype of meningioma, classified as Grade II by the World Health Organization due to its higher recurrence risk. While CCMs predominantly arise in the cerebellopontine angle, intraspinal cases, particularly those without dural attachment, are exceedingly rare and present diagnostic and surgical challenges.

We report a case of a 66-year-old woman who presented with a one-year history of pain and numbness radiating from the right buttock to the posterior thigh, along with intermittent claudication. Physical examination showed no motor deficits or significant neurological abnormalities. Magnetic resonance imaging revealed a 32 × 16 mm intradural mass at the L5 level with iso-intensity on both T1- and T2-weighted images and uniform contrast enhancement. The lesion was diagnosed as CCM based on pathological examination following tumor resection.

The patient underwent lumbar laminectomy and complete tumor resection. Intraoperatively, the tumor was observed to compress the cauda equina nerve but was nonadherent to the dura mater. A nerve fiber connected the tumor to surrounding neural structures, requiring partial nerve root resection for complete tumor removal. Postoperatively, the patient reported complete resolution of pain, numbness, and gait disturbance. The visual analogue scale scores for leg pain and numbness improved from 7.4 and 7.3 to 0, respectively. The Japanese Orthopaedic Association score improved from 22 to 28 (out of 29). Follow-up magnetic resonance imaging at 1 year showed no evidence of recurrence.

CCM without dural attachment is a rare variant of meningioma that presents challenges in diagnosis and surgical management. Complete resection during the first surgery led to favorable outcomes in this case. Although the recurrence rate for this subtype is lower, long-term follow-up with regular imaging is recommended.