Atypical fibroxanthoma (AFX) is a type of skin cancer which usually appears on the face or neck of the elderly when the skin has been highly damaged by sun exposure or previous radiation therapy. The lesions usually appear as a small nodule and grow to 2-3 cm. over a period of about 6 months.
Difference in Opinion on Classification
There has been debate over how AFX should be classified. According to Dr. Phillip McKee in his paper, What is Atypical Fibroxanthoma? Carcinoma, Sarcoma, Both or Neither?" "AFX has been a source of much controversy. It has been variously considered a reactive process, a benign tumor, an intermediate tumor, a low grade malignant tumor"a further school of thought believes that AFX as an entity does not even exist. It believes"it should be given the diagnosis they deserve: squamous cell carcinoma."  However, a study completed in 2005 by B. Mirza and D. Weedon in Australia concluded that, "our data suggest it is unlikely that atypical fibroxanthoma is a variant of squamous cell carcinoma."
According to a study published in 2011 in the journal Clinical and Experimental Otorhinolaryngology, AFX occurs most often in older Caucasians, although it can rarely occur in the Asian population.  Some of the characteristics include;
A small nodule usually appears around the ears, nose, cheeks and back of the neck. It is normally a solitary tumor
The nodule may be ulcerated or crusted
The tumor usually grows to about 2 o 3 cm. over about 6 months
AFX can recur although it does not normally metastasize.
The most effective treatment for AFX is excision. Because the margins of the tumor are not always clearly defined, wide excision is more often recommended than a narrow excision of the tumor. Mohs surgery has also been used because this type of surgery removes the tumor while protecting surrounding healthy tissue.
 Atypical Fibroxanthoma: A Clinicopathological Study of 89 Cases," 2005, B. Mirza, D. Weedon, Mater Adult Hopsital
 "Atypical Fibroxanthoma in Head and Neck," 2011, Jin Pyeong Kim, M.D. et al, Gyeongsang National University College of Medicine