Cutaneous atypical fibroxanthoma (AFX) occurs in elderly persons as a small nodule or ulceronodule in actinically damaged skin of the head and neck area. The vast majority of AFX behave in a benign manner, and metastasis is rare. Eight examples of metastasizing AFX are reported. Factors that portend aggressive behavior and metastasis are vascular invasion, recurrence, deep tissue invasion, tumor necrosis and, possibly, defective or depressed host resistance. The metastasizing primary AFX were located on the head, and the metastasis involved the structures in the region of the parotid gland.Cancer 57:368-376, 1986.UTANEOUS ATYPlCAL FIBROXANTHOMA (AFX)C usually occurs in the elderly as a small nodule or ulceronodule in actinically damaged skin of the head and neck. Histologically, an anaplastic appearance with multiplicity of cell types, marked cytologic atypia, bizarre giant cells, and abundant mitotic activity are characteri~tic.l-~ Paradoxically, the clinical course of atypical fibroxanthoma is almost always benign. Recurrent tumors are mentioned in most recorded series,2-8 but reports of metastasizing AFX are a rarity.2,R-'0 Eight cases of metastasizing AFX were studied to ascertain histologic and clinical factors that might aid in differentiating the aggressive lesions from the usual AFX. Seven are initially reported, and one was recorded previously.9
Materials and MethodsReview of the material on file at the Armed Forces Institute of Pathology revealed eight cases of AFX with clinical and histologic evidence of metastasis. All lesions met the established histologic criteria for AFX and were of dermal origin.2 Lesions that appeared to arise in the subcutaneous tissue or in deeper tissues were excluded. The cases were contributed by civilian pathologists and by pathologists of the Veterans Administration and the Military Services. Follow-up questionnaires were sent to pathologists, clinicians, and patients.