title: Cutaneous PEComa does not harbour TFE3 gene fusions: immunohistochemical and molecular study of 17 cases.
abstract: OBJECTIVE
  The family of perivascular epithelioid cell tumours (PEComas) comprises a related group of mesenchymal tumours of uncertain origin that show both smooth muscle and melanocytic differentiation markers. TFE3 nuclear immunoreactivity may be viewed as a supporting marker, as it has been found in a subset of visceral PEComas. We immunohistochemically analysed 17 cases of primary cutaneous PEComas for TFE3, and five of them also for SOX-10, and also analysed them by FISH for TFE3 rearrangement.
  
  
  RESULTS
  PEComas presented as skin-coloured tumours, in 12 women and five men, with a median age of 49.5 years. Tumours showed either a mixed clear cell-epithelioid cell pattern or a monomorphous clear cell pattern. None of the primary cutaneous PEComas showed detectable TFE3 or SOX-10 positivity. FISH assay for TFE3 rearrangement yielded negative results in all of the tested tumours.
  
  
  CONCLUSIONS
  Cutaneous PEComas are mostly composed of clear cells, and, unlike a subset of visceral and deep-seated PEComas, cutaneous PEComas consistently lack TFE3 expression. Owing to the lack of SOX-10 expression, a neural crest origin could not be shown.
authors.affiliation: Department of Dermatology, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Llamas-Velasco
authors.forename: Thomas
authors.initials: T
authors.lastname: Mentzel
authors.forename: Luis
authors.initials: L
authors.lastname: Requena
authors.forename: Gabriele
authors.initials: G
authors.lastname: Palmedo
authors.forename: Robert
authors.initials: R
authors.lastname: Kasten
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
mesh_terms: D000328:Adult; D000368:Aged; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D050939:Gene Fusion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D054973:Perivascular Epithelioid Cell Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D055757:SOXE Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; C069203:TFE3 protein, human