Atypical Fibroxanthoma

This picture demonstrates several multinucleated giant cells and an atypical mitotic figure. Mitotic figures generally fall within 5-10 per 10 high powered fields. Despite the high-grade morphologic features, atypical fibroxanthoma is an indolent lesion with excellent prognosis. Local excision usually is curative. Recurrences are uncommon. Rare cases have exhibited aggressive behavior and the features associated with such cases include vascular invasion, invasion of deep soft tissues, necrosis, history of multiple recurrences, and the presence of immunosuppression. Some authors consider atypical fibroxanthoma to be a distinct subtype of malignant fibrous histiocytoma.