Figure 1

Histological features of the lesion showing colonic mucosa with diffuse Schwann cell proliferation within the lamina propria. Spindle cells with elongated nuclei and no cytological atypia; low-power magnification, H&E staining (a); the lesion shows strong immunoreactivity for S-100 protein (b) and no immunoreactivity for CD117 (c) or smooth muscle actin (d).