Figure 4. Histological findings. a. Cystic spaces with hemorrhage are found in the tumor (hematoxylin-eosin stain, x5). b. The tumor shows closely packed spindletumor cells corresponding with Antoni A area (hematoxylin and eosin x50). c. Fewer cellular areas (Antoni B area) with many hemosiderin-laden histiocytes are also observed (hematoxylin and eosin x100). d. Tumor cells are strongly positive for S-100 protein (x50).