Clear cell meningioma of the cauda equina in an adult: case report and literature review

In the pediatric population, clear cell meningiomas are more frequently intracranial than intraspinal in location. Tumors recur in up to 40% of cases within 15 postoperative months and are often managed with repeated resection with or without radiation therapy. The management strategy for adults with clear cell meningiomas involving the lumbar spinal canal (cauda equina) is less clearly defined. A 41-year-old woman presented with mild, right greater than left, lower extremity paresis. An enhanced magnetic resonance (MR) scan revealed a homogeneously enhancing intradural lesion filling the spinal canal at the L3-L4 level. Preoperative noncontrast MR studies of the brain and cervical and thoracic spine were negative. An L2-L5 laminectomy was performed for gross total excision of the intradural lesion, which was adherent to one nerve root of the cauda equina. Frozen-section diagnosis confirmed clear cell tumor. Differential diagnoses included meningioma versus renal cell carcinoma. Negative postoperative chest, abdominal, and pelvic computed tomography studies ruled out tumor of renal cell origin. Enhanced MR studies of the neuraxis proved negative. Consultations with multiple oncologists and radiation therapists recommended neither radiation nor chemotherapy following this initial surgery. She remains disease-free 1 year postoperatively. The high recurrence rate for clear cell meningiomas in children requires repeated tumor resection with or without secondary radiation therapy. Following gross total resection of lumbar tumors in adults, reserving radiation therapy for secondary recurrences provides optimal management.