Sections are of skin. Within the dermis is a poorly circumscribed proliferation of spindle cells arranged in fascicles. The cells have a moderate amount of eosinophilic cytoplasm. The nuclei are elongated with blunt ends and inconspicuous nucleoli. Mitotic figures are easily identified. The spindle cells exhibit strong cytoplasmic immunostaining for desmin. S-100 and factor VIII immunostains are negative in the spindle cells.