Figure 4.

(A) Low nuclear Ki-67 immunoreactivity (×200) indicating low tumor cell proliferation rate. (B) Neoplasm composed of cytologically bland spindle cells arranged in intersecting fascicles with nuclear palisading. No histologic features of malignancy are identified. (H&E, ×200). Arrows indicate Antoni A, densely packed cells, and star presents Antoni B area with loosely organized cells. (C) S100 immunohistochemical stain (×200) of surgically resected tumor showed strongly positive diffuse nuclear and cytoplasmic staining for S-100 protein.