Aberrant Melan-A expression in atypical fibroxanthoma and undifferentiated pleomorphic sarcoma of the skin

Chee Thum, Kevin Hollowood, Jeremy Birch, John Goodlad, Thomas Brenn

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Atypical fibroxanthoma (AFX) is a distinctive clinicopathologic entity presenting on sun-damaged skin of the elderly. Its behavior is benign if strict diagnostic criteria are applied. Tumors showing invasion of deeper structures or perineural/lymphovascular invasion are best regarded as undifferentiated pleomorphic sarcoma of the skin. The diagnosis requires immunohistochemical studies to exclude melanoma, squamous cell carcinoma, angiosarcoma and leiomyosarcoma.

METHODS: Two AFX and one undifferentiated pleomorphic sarcoma showing aberrant expression of Melan-A were identified. Clinical data were obtained and histopathological features, immunohistochemical profile and electron microscopy were assessed.

RESULTS: All tumors arose on sun-damaged skin of elderly males. Two AFX showed pushing growth into superficial subcutis only. The undifferentiated pleomorphic sarcoma was characterized by infiltrative growth into galea as well as perineural invasion. Multifocal expression of Melan-A and MART-1 was largely limited to tumor giant cells in the absence of S100 or HMB-45 labeling. No melanosomes or premelanosomes were identified by electron microscopy.

CONCLUSIONS: Aberrant expression of Melan-A and MART-1 in AFX and undifferentiated pleomorphic sarcoma of the skin represents an important diagnostic pitfall with potential for misdiagnosis as melanoma.

Original languageEnglish
Pages (from-to)954-60
Number of pages7
JournalJournal of Cutaneous Pathology
Volume38
Issue number12
DOIs
Publication statusPublished - Dec 2011

Keywords

  • Aged
  • Dermatofibrosarcoma
  • Diagnosis, Differential
  • Fibroma
  • Gene Expression Regulation, Neoplastic
  • Humans
  • MART-1 Antigen
  • Male
  • Skin Neoplasms
  • Xanthomatosis

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