|
| Fig. 47.5 Atypical fibroxanthoma arising on a sun-damaged hand. |
AFX is a superficial mesenchymal dermal tumor that microscopically shows high-grade cytologic atypia. It most commonly presents in the elderly as a nondistinct solitary dome-shaped nodule in sun-damaged skin, usually of the head and neck (Fig. 47-5). Ulceration is variably present. Histologically, it demonstrates a cellular dermal tumor with an epidermal collarette. Skin adnexa are generally surrounded but not destroyed by the tumor, and the deep margin is generally pushing rather than infiltrative. The tumor is composed of spindle and epithelioid cells arranged in disordered fascicles, with striking pleomorphism and atypia of the cells and numerous mitosis.
