Histopathological Investigation of Dura-like Membrane in Vestibular Schwannomas

The dura-like membrane (DLM) is an outermost membranous structure arising from the dura mater adjacent to the internal auditory meatus (IAM) that envelops some vestibular schwannomas (VSs). Its recognition is important for the preservation of the facial and cochlear nerves during tumor resection. This study analyzes the histopathological characteristics of the DLM. The expression of CD34 and alpha SMA was histopathologically analyzed in tumor and DLM tissue of 10 primary VSs with and without a DLM. Tumor volume, resection volume percentage, microvessel density (MVD), and vessel diameter were analyzed. Volumetric analysis revealed that the presence of a DLM was significantly associated with lower tumor resection volume (p < 0.05). Intratumoral vessel diameter was significantly larger in the DLM group than the non-DLM group (p < 0.01). Larger VSs showed a higher intratumoral MVD in the DLM group (p < 0.05). Multilayered alpha SMA-positive vessels were identified in the DLM, tumor, and border; there tended to be more of these vessels within the tumor in the DLM group compared to the non-DLM group (p = 0.08). These arteriogenic characteristics suggest that the DLM is formed as the tumor induces feeding vessels from the dura mater around the IAM.

Automated summary

The dura-like membrane (DLM) is an membranous structure arising from the dura mater adjacent to the internal auditory meatus that envelops some vestibular schwannomas (VSs). Recognition of DLM is important for preserving facial and cochlear nerves during tumor resection. The study found that the presence of DLM was associated with lower tumor resection volume, larger intratumoral vessel diameter, and higher intratumoral microvessel density.