**4. Pathology**

Schwannomas are benign Schwann cell tumors that, when in the central nerve system, affect sensitive roots. The most frequent location is in the vestibular root of the VIII and rarely is present in the trigeminal location. Microscopically, the tumor is formed by elongated cells, arranged in bundles that intersect. The nuclei tend to be arranged parallel to each other, an aspect called the arrangement in palisades, very typical of the schwannoma. The spaces with few nuclei between palisades are constituted only by the cytoplasm of Schwann cells and are called bodies of Verocay. There is no necrosis or mitosis (**Figure 8**).

**Figure 8.** On the left side, an increase of 400× shows benign fusocellular neoplasia next to blood vessels with thickened walls. On the right side, immunohistochemistry with a magnification of 400×, presenting strong expression of neoplastic cells to protein S100.
