Hyalinizing clear cell carcinoma with EWSR1-ATF1 fusion gene: report of three cases with molecular analyses

Virchows Arch. 2015 Jan;466(1):37-43. doi: 10.1007/s00428-014-1676-5. Epub 2014 Oct 31.

Abstract

Hyalinizing clear cell carcinoma (HCCC) is a low-grade salivary gland carcinoma characterized by clear cells and hyalinized stroma. Recently, the EWSR1-ATF1 fusion gene was found in HCCCs. We herein describe three cases of HCCC identified in one male and two females, ranging in age from 27 to 67 years. The tumors were located in the root of tongue, nasopharynx, and soft palate. They were composed of nested or cord-like proliferations of epithelial cells with clear to pale eosinophilic cytoplasm, embedded in hyalinized and focally fibroedematous stroma. Tumor-associated lymphoid proliferation and pseudoepitheliomatous hyperplasia were also observed in each one case. MAML2 fusions specific to mucoepidermoid carcinoma were not detected in any of the three cases. We found EWSR1-ATF1 in two of three HCCCs using reverse transcription polymerase chain reaction (RT-PCR) with our original primer sets designed to detect the fusion gene transcripts in formalin-fixed paraffin-embedded (FFPE) tissues. EWSR1 rearrangement was also confirmed by fluorescence in situ hybridization (FISH) on FFPE sections in two cases. There was a good concordance between the two methods (two positive cases and one negative case by both RT-PCR and FISH). Therefore, RT-PCR and FISH using FFPE tissue may be ancillary tools to confirm the diagnosis of HCCC.

Publication types

  • Case Reports

MeSH terms

  • Activating Transcription Factor 1 / genetics*
  • Adenocarcinoma, Clear Cell / diagnosis
  • Adenocarcinoma, Clear Cell / genetics*
  • Adenocarcinoma, Clear Cell / metabolism
  • Adult
  • Aged
  • Calmodulin-Binding Proteins / genetics*
  • Female
  • Gene Fusion / genetics*
  • Gene Rearrangement / genetics
  • Humans
  • Hyalin / metabolism*
  • In Situ Hybridization, Fluorescence
  • Male
  • Middle Aged
  • Nasopharynx
  • Palate, Soft
  • Polymerase Chain Reaction
  • RNA-Binding Protein EWS
  • RNA-Binding Proteins / genetics*
  • Salivary Gland Neoplasms / diagnosis
  • Salivary Gland Neoplasms / genetics*
  • Salivary Gland Neoplasms / metabolism
  • Tongue

Substances

  • ATF1 protein, human
  • Activating Transcription Factor 1
  • Calmodulin-Binding Proteins
  • EWSR1 protein, human
  • RNA-Binding Protein EWS
  • RNA-Binding Proteins