Lumbar interdural meningioma: A case report and anatomical considerations.

BACKGROUND: Interdural spinal meningiomas, arising between dural layers, are exceptionally rare. CASE DESCRIPTION: A 50-year-old male presented with a 2-month history of lower back pain and numbness in the left L2-L3 dermatome. The magnetic resonance imaging (MRI) demonstrated a 25 × 14 × 8 mm, well-circumscribed, extradural-appearing mass at L2 with extension into the left L2/3 foramen. The lesion was hypointense on the T2WI and T2 heterogeneously enhanced with gadolinium. The preoperative differential diagnosis included schwannoma and extradural meningioma. At surgery, the lesion was entirely interdural. Complete resection was achieved with preservation of the inner dural layer. Histopathological examination confirmed a metaplastic meningioma with extensive chondroid metaplasia. The patient's symptoms resolved completely, and at 7 postoperative months, the MRI showed no recurrence. CONCLUSION: Here, we report an interdural L2-L3 meningioma that was completely resected while preserving the inner dural layer.