Atypical fibroxanthoma—a diagnosis of exclusion!

Abstract

Fibrohistiocytic tumors of the skin comprise a large range of lesions. One such tumor is the atypical fibroxanthoma (AFX), which is widely considered as a "pseudomalignant" tumor. It is derived from fibroblasts and expresses a variety of histiocytic markers. We present a case of AFX, localized in the right temporal region of the scalp, successfully treated with surgical excision. Immunohistochemical staining helps differentiate this tumor from others in the clinical differential diagnosis, including malignant melanoma, squamous cell carcinoma, and other nonmelanocytic spindle cell tumors such as leiomyosarcoma, rhabdomyosarcoma, angiosarcoma, liposarcoma, and dermatofibrosarcoma protuberans. Historically, AFX was believed to be a superficial variant of malignant fibrous histiocytoma (MFH). However, MFH is now considered a more generalized term for a sarcomatous neoplasm of the subcutaneous tissue. The histopathology of MFH shares features with some malignant mesenchymal neoplasms such as liposarcoma, leiomyosarcoma, rhabdomyosarcoma, and angiosarcoma, but can be differentiated using immunohistochemistry and/or electron microscopy. More recently, the examples of MFH that do not exhibit a more specific line of differentiation have been reclassified as undifferentiated pleomorphic sarcoma (UPS). Many authors currently cannot draw a distinction between AFX and UPS. The clinical and histopathological differences between AFX and UPS are often difficult to delineate. It is probable that they represent two poles of the same disease. Surgical excision in the patient we describe resulted in excellent aesthetic results with lack of recurrence in the 7-month postoperative period.

Atypical fibroxanthoma management: Recurrence, metastasis and disease‐specific death

“…There were 218 cases from 10 eligible studies citing MMS as the main mode of treatment (Table ). Compiled recurrence rates were 4.6%, and metastasis rates were 3.2%.…”

Atypical fibroxanthoma: new insights

“…AFX has a mesenchymal origin (fibroblastic, fibrohistiocytic or myofibroblastic nature), that is, it may be derived from fibroblasts, fibrohistiocytes or myofibroblasts [59,67,81]. In 1973, VargasCortes et al suggested that AFX may arise from the tissue histiocytes.…”

A bone fide atypical fibroxanthoma of penis

“…[3] Current opinions and evidence of clinical and diagnostic differences between AFX and MFH are pointed to consider AFX as a distinct entity with MFH/UPS. [45] The AFX generally arises on the skin damaged by radiation, particularly in solar phototype subjects below. Often it is localized in areas such as head and neck of elderly patients surrounded by areas with apparent actinic damage; moreover, it may localize on burn scars.…”