Atypical Fibroxanthoma (AFX)

Epidemiology:

• elderly

Common sites:

• Skin of face (sun exposed)

Gross features:

• Usually ulcerated

Histologic features:

• same as malignant fibrous histiocytoma
• don’t call it AFX unless you see the base
• tumour occupying dermis and sometimes superficial subcutaneous tissue
• well-defined lesion
• often intimate epidermal contact
• highly pleomorphic cells, vaguely spindle-shaped
• may have xanthomatous cells
• abundant mitoses and very atypical mitoses
• rule out all other sarcomas

Immunophenotype:

Marker:	Sensitivity:	Specificity:
CD68		poor

Molecular features:

Other features:

• paradoxically benign clinical behaviour