Study design: Histological observational study of patients with spinal meningioma.
Objective: To clarify the status of tumor cell invasion into the dura mater and to provide fundamental information for appropriate management of dural attachment.
Summary of background data: Histological appearance of the dura attached to spinal meningioma has not been sufficiently evaluated.
Methods: Dura mater resected in a Simpson Grade 1 manner from 25 consecutive patients with spinal meningiomas (World Health Organization grade 1) was histologically observed to determine the status of tumor cell invasion. As no clear borders such as a tumor capsule between tumor and dura mater were observed, histological findings of the dura mater were classified into the following 3 categories: grade 1, no dural invasion, with only inflammation of the dura; grade 2: dural invasion below the zone between the inner and outer layers; and grade 3, dural invasion into or over the zone between the inner and outer layers (full-thickness invasion).
Results: In our microscopic study, 19 of the 25 cases of spinal meningioma showed evidence of dural invasion and 15 cases showed full-thickness invasion.
Conclusion: This histological investigation of resected dura mater attached to spinal meningioma showed a high rate of full-thickness tumor invasion into the dura mater.