Atypical fibroxanthoma

Atypical fibroxanthoma (AFX) is an uncommon, pleomorphic, spindle cell cutaneous malignancy that most commonly presents as a solitary red or pink papule or nodule on the sun-exposed skin of elderly individuals. It has invasive potential, may recur locally after excision, and very rarely metastasizes.

The relationship between AFX, pleomorphic dermal sarcoma, and undifferentiated pleomorphic sarcoma (UPS), a soft tissue neoplasm that shares many histologic features with AFX, is unclear. While some authors consider AFX a less aggressive, superficial variant of pleomorphic dermal sarcoma and UPS, most view AFX as a distinct malignancy.

This chapter is set out as follows: 

Risk factors for AFX include:

• Age - AFX has a peak incidence in the seventh to eighth decades of life; in one study the mean age at presentation was 76 
• Sex - more common in men
• UV-exposure
• Fair-skinned individuals 
• A past history of non-melanoma skin cancer
• Previous radiotherapy  
• Immunosuppression 

Distribution

• Predominantly UV-damaged skin - most lesions are located on the head and neck

Morphology

• Red, juicy, dome-shaped nodules that may be ulcerated or crusted 
• Lesions often grow rapidly, and rarely exceed 3 cm in diameter
• The surrounding skin often shows signs of actinic damage 

• Atypical fibroxanthomas can have similar appearances to SCC or other skin malignancies and so patients with such lesions should be referred on an urgent skin cancer pathway  
   
• Most are treated by standard excision to include a margin of normal skin. Mohs micrographic surgery is sometimes used for large or recurrent lesions
   
• Prognosis - a systematic review in 2025 of 1366 patients across eight studies observed a local recurrence rate of 4.73%, metastatic rate of 0.59% (8 out of 1366 patients), and no disease-related deaths, which reinforces the trend of favourable prognosis associated with AFX. Complications are most commonly observed in immunosuppressed patients