Atypical Fibroxanthoma

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Background

Atypical fibroxanthoma (AFX) is a tumor that occurs primarily in older individuals after the skin of the head and neck has been damaged significantly by sun exposure and/or therapeutic radiation. Clinically, lesions usually are suggestive of malignancy because they arise rapidly (over just a few weeks or months) in skin in which other skin cancers have been found and treated. When this clinical impression is combined with highly anaplastic pathology, misdiagnosis can result in unnecessary and extensive surgery and radiation. The image below demonstrates the typical clinical presentation of an atypical fibroxanthoma.



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Red, beefy, sessile nodule typical of clinical presentation of atypical fibroxanthoma. Note the markedly sun-damaged skin with solar telangiectasias. ....

Histologically, lesions show a highly atypical and pleomorphic cellular appearance, but they typically respond to simple excision. Clinicopathologic correlation is essential. Factors important to consider are lesion location, patient age, histopathologic appearance, and the observation that the tumor arises from the dermis, not the fat. Many AFX tumors may represent a superficial form of malignant fibrous histiocytoma (MFH) with a much better prognosis. Some cases may represent primary squamous cell carcinoma (SCC) that fails to express keratin.

Etiology

Sun exposure and/or therapeutic radiation that have caused significant skin damage are associated with the development of atypical fibroxanthoma (AFX). The tumor primarily occurs on the head or neck of older individuals.

Epidemiology

Sex

Male-to-female ratio is equal.

Age

In one study, age ranged from 13-95 years with a mean age of 69 years.

History

Typically, the patient presenting with atypical fibroxanthoma (AFX) is an older individual (mean age 69 y) with sun-damaged or radiation-damaged skin of the head, neck, and scalp.

Physical Examination

Nodules are red, juicy, and dome shaped and they may be ulcerated, as in the image below. Lesions are usually located on skin that is red, thin, and telangiectatic, indicating previous significant sun or radiation damage. Some nodules are dark enough, due to deposits of hemosiderin, to be confused with a nodular melanoma.



View Image

Red, beefy, sessile nodule typical of clinical presentation of atypical fibroxanthoma. Note the markedly sun-damaged skin with solar telangiectasias. ....

Nodules primarily are located on the head and neck and in sun-exposed areas. In addition, lesions have been reported to occur on the trunk, extremities, and in sun-protected areas. The ratio of lesions that occur on the head and neck to lesions that occur in other areas is approximately 4:1.

Tumor size increases proportionately with duration of existence but rarely exceeds 3 cm in diameter. Lesion growth typically is rapid, and patients usually seek medical advice within 6 months of onset.

In adult cases, the skin underlying developing atypical fibroxanthoma (AFX) lesions may be considered locally immunosuppressed. Reports have shown an increased incidence of AFX in patients with AIDS and in patients who are immunosuppressed because of organ transplantation.

One case of localized cutaneous metastases has been reported after excision of the primary lesion. This is extremely rare.

Laboratory Studies

The following laboratory tests may be needed:

Other Tests

Dermoscopy may be helpful (see Histologic Findings).

Histologic Findings

The pathologic appearance of atypical fibroxanthoma (AFX) belies the usually excellent prognosis. As shown in the image below, this nonencapsulated dermal tumor is composed of large, fibrocytic, spindle-shaped and anaplastic cells arranged in a haphazard fashion, occasionally in fascicles, and usually with an increased number of mitotic figures. Large histiocytic cells may form bizarre multinucleated giant cells that frequently contain lipid, contributing to the tumor's name. Phagocytosis of erythrocytes has been demonstrated, resulting in hemosiderin pigmentation within a lesion and causing clinical confusion with malignant melanoma.[2] Granular and clear cell variants have been reported.[3, 4, 5, 6]



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Microscopic view of atypical fibroxanthoma. Note the large abnormal-appearing cells in a field of spindle cells. Courtesy of Capt James Steger, MC, US....

Electron microscopy [7]

Electron microscopy suggests a fibrohistiocytic nature in the tumor. A transition from fibroblast to large giant cells can be seen, with intermediate forms that exhibit features of both cell types. Pathologic findings in AFX appear to be more related to MFH than to either dermatofibroma or dermatofibrosarcoma protuberans (DFSP). Delicate cytoplasmic fibrils were seen in one case studied with electron microscopy, but these fibrils were not considered to arise from myofibroblasts and findings did not support a muscle origin for AFX.

Immunohistochemistry

Panels of specific antibodies together with the tumor's histologic pattern help differentiate AFX from other types of spindle cell skin lesions.[8] Specific and critical differences of antibody reactivity (R) and nonreactivity (N) are demonstrated in the Table.

Table. Antibody Panels in Tumors



View Table

See Table

 SCC, spindle cell MM, and leiomyosarcoma usually are differentiated using immunocytochemistry. No reliable consistent immunocytochemistry method is specific for AFX, and the diagnosis is based on typical histologic findings and the absence of immunomarker positivity for melanocytes, keratin, and smooth muscle actin.

DNA content quantification [9, 10]

Diploid or euploid cells have pairs or multiple pairs of chromosomes and usually are considered benign. Aneuploid cells have single or multiple single sets of chromosomes and are more common in malignant neoplasms.

Attempts to evaluate chromatin content in AFX have resulted in much confusion because of the methods of evaluation. The average picture produced with flow cytometry suggests that AFX is diploid. Using individual cell analysis, aneuploidy was found in giant cells, while diploidy has been found in smaller spindle-shaped cells. This picture is similar to MFH and does not allow nuclear cytometry to differentiate between MFH and AFX.

Dermoscopic features

A diagnosis of AFX is often not suspected clinically. The histologic findings of the biopsy specimen may cause great consternation, bringing to mind serious and possibly life-threatening diagnoses. Only by combining the clinical presentation with specific staining panels to eliminate other suspected diagnoses is the correct one determined. Although dermatoscopic features of the tumor have been reported, they are not specific. Bugatti and Filosa found white areas and an atypical polymorphous vascular pattern characterized by linear, dotted, hairpin and arborescent vessels irregularly distributed over the surface of the tumor.[11]

Histologic variants

Nonpleomorphic AFX (spindle cell AFX) was reported by Calonje et al in a series of cases of sun-damaged skin of the head and neck in older individuals.[12] The immunocytochemistry findings and the tumors' benign clinical course supported the diagnosis of AFX. Pathologically, lesions were monomorphic, spindle-celled, fascicular variants without pleomorphic cells. All lesions were vimentin positive with approximately 50% showing focal actin activity. Desmin, keratin, and S-100 protein were negative in all cases. Other variants with clear cells, osteoclastic-type cells, and granular cells have been reported.

Surgical Care

In the past, many lesions were diagnosed clinically as pyogenic granuloma and removed by shave and curettage, without recurrence, which has prompted physicians to treat atypical fibroxanthoma (AFX) conservatively. Local recurrence and spread to lymph nodes may occur.[13, 14] This suggests that complete tumor removal is required. Simple excision with a margin of normal skin or Mohs micrographic surgery may be appropriate.

Mohs micrographic surgery, with its high reliability of complete tumor removal and tissue-conserving property, is an excellent choice for AFX on the head and neck.[15, 16, 17, 18]

Prevention

Instruct patients to avoid excessive sun exposure.

What is atypical fibroxanthoma (AFX)?What causes atypical fibroxanthoma (AFX)?What are the sexual predilections of atypical fibroxanthoma (AFX)?Which age groups have the highest prevalence of atypical fibroxanthoma (AFX)?Which clinical history findings are characteristic of atypical fibroxanthoma (AFX)?Which physical findings are characteristic of atypical fibroxanthoma (AFX)?Which conditions should be included in the differential diagnoses of atypical fibroxanthoma (AFX)?What are the differential diagnoses for Atypical Fibroxanthoma?Which lab tests are performed in the workup of atypical fibroxanthoma (AFX)?Which histologic findings are characteristic of atypical fibroxanthoma (AFX)?What is the role of electron microscopy in the diagnosis of atypical fibroxanthoma (AFX)?What is the role of immunohistochemistry in the diagnosis of atypical fibroxanthoma (AFX)?What is the role of DNA content quantification in the diagnosis of atypical fibroxanthoma (AFX)?What is the role of dermoscopy in the diagnosis of atypical fibroxanthoma (AFX)?What are the histologic variants of atypical fibroxanthoma (AFX)?What is the role of surgery in the treatment of atypical fibroxanthoma (AFX)?How is atypical fibroxanthoma (AFX) prevented?

Author

Forrest C Brown, MD, Clinical Professor of Dermatology, University of Texas Southwestern Medical School; Section Chief, Department of Dermatology, Medical City Dallas Hospital

Disclosure: Nothing to disclose.

Specialty Editors

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine; Consulting Staff, Mountain View Dermatology, PA

Disclosure: Nothing to disclose.

Rosalie Elenitsas, MD, Herman Beerman Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System

Disclosure: Received royalty from Lippincott Williams Wilkins for textbook editor.

Chief Editor

William D James, MD, Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

Disclosure: Received income in an amount equal to or greater than $250 from: Elsevier; WebMD.

Additional Contributors

Carrie L Kovarik, MD, Assistant Professor of Dermatology, Dermatopathology, and Infectious Diseases, University of Pennsylvania School of Medicine

Disclosure: Nothing to disclose.

References

  1. Hussein MR. Atypical fibroxanthoma: new insights. Expert Rev Anticancer Ther. 2014 Sep. 14(9):1075-88. [View Abstract]
  2. Diaz-Cascajo C, Borghi S, Bonczkowitz M. Pigmented atypical fibroxanthoma. Histopathology. 1998 Dec. 33(6):537-41. [View Abstract]
  3. Requena L, Sangueza OP, Sanchez Yus E, Furio V. Clear-cell atypical fibroxanthoma: an uncommon histopathologic variant of atypical fibroxanthoma. J Cutan Pathol. 1997 Mar. 24(3):176-82. [View Abstract]
  4. Bedir R, Agirbas S, Sehitoglu I, Yurdakul C, Elmas O. Clear cell atypical fibroxantoma: a rare variant of atypical fibroxanthoma and review of the literature. J Clin Diagn Res. 2014 Jun. 8(6):FD09-11. [View Abstract]
  5. Nemejcová K, Dundr P. Granular cell variant of atypical fibroxanthoma. A case report. Cesk Patol. 2014 Winter. 50(1):34-37. [View Abstract]
  6. Rudisaile SN, Hurt MA, Santa Cruz DJ. Granular cell atypical fibroxanthoma. J Cutan Pathol. 2005 Apr. 32(4):314-7. [View Abstract]
  7. Starink TH, Hausman R, Van Delden L, Neering H. Atypical fibroxanthoma of the skin. Presentation of 5 cases and a review of the literature. Br J Dermatol. 1977 Aug. 97(2):167-77. [View Abstract]
  8. Singh M, Mann R, Ilankovan V, Hussein K, D'arrigo C. Atypical Fibroxanthoma-A Retrospective Immunohistochemical Study of 42 Cases. J Oral Maxillofac Surg. 2012 Apr 9. [View Abstract]
  9. Michie BA, Reid RP, Fallowfield ME. Aneuploidy in atypical fibroxanthoma: DNA content quantification of 10 cases by image analysis. J Cutan Pathol. 1994 Oct. 21(5):404-7. [View Abstract]
  10. Worrell JT, Ansari MQ, Ansari SJ, Cockerell CJ. Atypical fibroxanthoma: DNA ploidy analysis of 14 cases with possible histogenetic implications. J Cutan Pathol. 1993 Jun. 20(3):211-5. [View Abstract]
  11. Bugatti L, Filosa G. Dermatoscopic features of cutaneous atypical fibroxanthoma: three cases. Clin Exp Dermatol. 2009 Dec. 34(8):e898-900. [View Abstract]
  12. Calonje E, Wadden C, Wilson-Jones E, Fletcher CD. Spindle-cell non-pleomorphic atypical fibroxanthoma: analysis of a series and delineation of a distinctive variant. Histopathology. 1993 Mar. 22(3):247-54. [View Abstract]
  13. Giuffrida TJ, Kligora CJ, Goldstein GD. Localized cutaneous metastases from an atypical fibroxanthoma. Dermatol Surg. 2004 Dec. 30(12 Pt 2):1561-4. [View Abstract]
  14. Grosso M, Lentini M, Carrozza G, Catalano A. Metastatic atypical fibroxanthoma of skin. Pathol Res Pract. 1987 Jun. 182(3):443-7. [View Abstract]
  15. Polcz MM, Sebaratnam DF, Fernández-Peñas P. Atypical fibroxanthoma management: Recurrence, metastasis and disease-specific death. Australas J Dermatol. 2017 Aug 17. [View Abstract]
  16. Zalla MJ, Randle HW, Brodland DG, et al. Mohs surgery vs wide excision for atypical fibroxanthoma: follow-up. Dermatol Surg. 1997 Dec. 23(12):1223-4. [View Abstract]
  17. Ang GC, Roenigk RK, Otley CC, Kim Phillips P, Weaver AL. More than 2 decades of treating atypical fibroxanthoma at mayo clinic: what have we learned from 91 patients?. Dermatol Surg. 2009 May. 35(5):765-72. [View Abstract]
  18. Fish FS. Soft tissue sarcomas in dermatology. Dermatol Surg. 1996 Mar. 22(3):268-73. [View Abstract]

Red, beefy, sessile nodule typical of clinical presentation of atypical fibroxanthoma. Note the markedly sun-damaged skin with solar telangiectasias. Courtesy of Capt James Steger, MC, USN, US Naval Hospital, San Diego.

Red, beefy, sessile nodule typical of clinical presentation of atypical fibroxanthoma. Note the markedly sun-damaged skin with solar telangiectasias. Courtesy of Capt James Steger, MC, USN, US Naval Hospital, San Diego.

Microscopic view of atypical fibroxanthoma. Note the large abnormal-appearing cells in a field of spindle cells. Courtesy of Capt James Steger, MC, USN, US Naval Hospital, San Diego.

Red, beefy, sessile nodule typical of clinical presentation of atypical fibroxanthoma. Note the markedly sun-damaged skin with solar telangiectasias. Courtesy of Capt James Steger, MC, USN, US Naval Hospital, San Diego.

Microscopic view of atypical fibroxanthoma. Note the large abnormal-appearing cells in a field of spindle cells. Courtesy of Capt James Steger, MC, USN, US Naval Hospital, San Diego.

Antibody AFX MFH SCC DFSP Spindle



MM*



Leiomyosarcoma
VimentinRRNRRR
CytokeratinNNRNNN
S-100NNNNRN
Desmin or smooth muscle actinNNNNNR
*Spindle cell malignant melanoma