MITF positivity in atypical fibroxanthoma: a diagnostic pitfall

Am J Dermatopathol. 2014 Nov;36(11):888-91. doi: 10.1097/DAD.0000000000000054.

Abstract

Microphthalmia transcription factor (MITF) is an established melanocytic marker originally credited with a high degree of specificity. We report a series of 11 atypical fibroxanthoma (AFX) from 2 laboratories showing positive MITF staining. Although there are multiple case reports illustrating MITF staining in a range of tumors, aberrant staining in AFX has not been previously reported. Awareness of the possibility of MITF positivity in AFX is important to avoid a misdiagnosis of melanoma. We also report positive MITF staining in 2 nonneural granular cell tumors and discuss the overlap with the granular subtype of AFX.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / analysis
  • Biopsy
  • Diagnostic Errors / prevention & control
  • Female
  • Fibroma / chemistry*
  • Fibroma / etiology
  • Fibroma / pathology
  • Humans
  • Immunohistochemistry
  • Male
  • Melanoma / chemistry
  • Melanoma / pathology
  • Microphthalmia-Associated Transcription Factor / analysis*
  • Middle Aged
  • Neoplasms, Radiation-Induced / chemistry*
  • Neoplasms, Radiation-Induced / etiology
  • Neoplasms, Radiation-Induced / pathology
  • New Zealand
  • Predictive Value of Tests
  • Skin Neoplasms / chemistry*
  • Skin Neoplasms / etiology
  • Skin Neoplasms / pathology
  • Sunlight / adverse effects

Substances

  • Biomarkers, Tumor
  • MITF protein, human
  • Microphthalmia-Associated Transcription Factor