Ocular PEComas are frequently melanotic and TFE3-translocated: report of two cases including the first description of PRCC-TFE3 fusion in PEComa

Virchows Arch. 2021 May;478(5):1025-1031. doi: 10.1007/s00428-020-02890-w. Epub 2020 Jul 16.

Abstract

Ocular perivascular epithelioid cell tumor (PEComa) is exceedingly rare. We reported two examples involving the choroid and subconjunctival tissue, respectively, in patients aged 17 and 20 years. Both tumors comprised packets and sheets of large polygonal cells with moderately pleomorphic nuclei and prominent nucleoli, traversed by delicate fibrovascular septa. Melanin pigmentation was present in one case. The tumors showed HMB45 and TFE3 immunoreactivity. TFE3 gene translocation was confirmed by FISH break-apart probes. RNA seq revealed PRCC-TFE3 and NONO-TFE3 fusions, with the former representing the first description of PRCC-TFE3 in PEComa. Critical reappraisal of the reported cases showed that ocular PEComa frequently affected young patents with melanin pigmentation, frequent TFE3 protein expression, and/or TFE3 gene translocation. No recurrence or metastasis was reported after complete excision despite the presence of cytologic atypia.

Keywords: Ocular; PEComa; PRCC-TFE3; RNA seq; TFE3.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adolescent
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics*
  • Biomarkers, Tumor / analysis
  • Biomarkers, Tumor / genetics*
  • Cell Cycle Proteins / genetics*
  • Choroid Neoplasms / chemistry
  • Choroid Neoplasms / genetics*
  • Choroid Neoplasms / pathology
  • Choroid Neoplasms / surgery
  • Eye Neoplasms / chemistry
  • Eye Neoplasms / genetics*
  • Eye Neoplasms / pathology
  • Eye Neoplasms / surgery
  • Female
  • Gene Fusion*
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Lacrimal Apparatus Diseases / genetics*
  • Lacrimal Apparatus Diseases / metabolism
  • Lacrimal Apparatus Diseases / pathology
  • Lacrimal Apparatus Diseases / surgery
  • Male
  • Melanins / analysis
  • Neoplasm Proteins / genetics*
  • Perivascular Epithelioid Cell Neoplasms / chemistry
  • Perivascular Epithelioid Cell Neoplasms / genetics*
  • Perivascular Epithelioid Cell Neoplasms / pathology
  • Perivascular Epithelioid Cell Neoplasms / surgery
  • RNA-Seq
  • Young Adult

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Biomarkers, Tumor
  • Cell Cycle Proteins
  • Melanins
  • Neoplasm Proteins
  • PRCC protein, human
  • TFE3 protein, human