Atypical fibroxanthoma: A review of the literature

Summary: Abstract Body: Atypical fibroxanthoma (AFX) is a rare, low-grade, dermal neoplasm. The purpose of this article is to review the current literature on AFX as it relates to epidemiology, clinical presentation, histopathology, immunohistochemistry, treatment, and prognosis. An extensive literature review was conducted using PubMed to identify articles related to AFX. AFX typically presents as a red nodule or plaque on the head and neck regions. Etiology is poorly understood, but it is believed that AFX arises from myofibroblasts or fibroblast-like cells and ultraviolet light exposure may play a role in pathogenesis. AFX is more common among the elderly of White race, however it has been reported in other patient populations as well. Skin biopsy is the gold standard for diagnosis, however, AFX has variable histological patterns which may cause AFX to be a diagnosis of exclusion. Histological patterning may include the following: spindle cell, clear cell, keloid-like, rhabdoid, pleomorphic, epithelioid, granular cell, bizarre cell, pseudoangiomatous, inflammatory, and many others. AFX is considered to be a superficial variant of undifferentiated pleomorphic sarcoma (UPS) because it is considered less aggressive with fewer genomic alterations. Further, Immunohistochemistry (IHC) staining may be helpful to exclude AFX from other skin cancers, as AFX can mimic UPS, squamous cell carcinoma, and melanoma. Notably, AFX will stain negative for HMB-45, seen with squamous cell carcinoma, as well as melanoma IHC stains: pan-cytokeratin stains and CD31. Although AFX has an excellent prognosis with low rates of recurrence, Mohs micrographic surgery has become the standard-of-care treatment as it allows for a reconstructive advantage and may decrease recurrence rates even further. Atypical fibroxanthoma is a low-grade tumor which has a favorable prognosis, however a classification system for histologic patterning is needed for a swifter diagnosis. Grace E. Steinback¹, Joycie Chang¹, Anand Rajpara¹ 1. School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States. Clinical Research: Epidemiology and Observational Research