. White individuals over aged 50 years are more frequently affected. Both genders are equally affected, and 25% of cases occur on the covered areas (trunk or extremities) of younger patients. Clinically, lesions present as pink to red plaques or nodules that exhibit rapid growth. Ulceration or crusting may be present. Causes of AFX include ultraviolet radiation and ionizing radiation. AFX is considered a superficial variant of malignant fibrous histiocytoma (MFH), the most common soft tissue sarcoma of adults. Clinically, MFH involves deeper tissues than does AFX, often on the thighs or buttocks. MFH is a more aggressive malignancy that regularly metastasizes.
Histologically, the tumor occurs as a dermal proliferation of “bizarre” spindle cells, epithelioid cells, and atypical histiocytes. Vesicular changes may be present in the nucleus or cytoplasm of the spindle cells. Mitotic figures are present. Multinucleated giant cells may be present. Solar elastosis is often seen, as well. Vimentin and histiocyte stains are positive. Unlike melanoma, S-100 staining is minimal. Unlike squamous cell carcinoma, prekeratin staining is negative. CD34 is negative. AFX resembles MFH histologically.
Surgical excision by the Mohs procedure is preferred over wide excision as there is a risk of recurrence. AFX rarely metastasizes. This is more likely if inadequately excised or the patient is immunosuppressed. Sun protective practices, such as applying and reapplying sunscreen regularly, wearing sun protective clothing, and avoiding excessive UV exposure during peak hours is recommended.
This case and photo were submitted by Dr. Bilu Martin.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at. To submit a case for possible publication, send an email to .