Extraskeletal myxoid chondrosarcoma of the vulva with PLAG1 gene activation: molecular genetic characterization of 2 cases

Appl Immunohistochem Mol Morphol. 2014 Aug;22(7):537-42. doi: 10.1097/PAI.0b013e31829852e7.

Abstract

Extraskeletal myxoid chondrosarcoma (EMC) is a rare mesenchymal neoplasm, rarely reported in the genitourinary tract with only 5 cases reported in the vulva. We investigated 2 cases of vulvar sarcomas whose morphologic appearance and immunohistochemical profiles were consistent with EMC using fluorescence in situ hybridization (FISH), reverse-transcription polymerase chain reaction, and a whole genome expression array. FISH and reverse-transcription polymerase chain reaction assays showed no EWSR1 and NR4A3 loci rearrangements. Microarray-based analysis also revealed no changes in NR4A3 and EWSR1 gene transcription levels. Microarray data showed a significant downregulation of the muscle-related genes (eg, myosin heavy chain family, actins, myoglobin, desmin, creatine kinase, troponins) and cytokeratins (KRT6A, 6B, 13, 14, and 78), upregulation of several neuron-specific genes [neural cell adhesion molecule 1 (NCAM-1/CD56), neurofilament (NEFH)], along with some well-characterized tumor biomarkers [carbonic anhydrase IX (CA-9), topoisomerase IIα (TOP2A), matrix metalloproteinases (MMP-7, MMP-9), CDKN2 gene (p16-INK4a), checkpoint homolog 2 (CHEK2)]. Notably, both tumors showed upregulation of the pleomorphic adenoma gene 1 (PLAG1), and in 1 case PLAG1 gene rearrangement was detected by break-apart FISH. Some vulvar tumors with morphologic and immunohistochemical characteristics of EMC may represent a molecular genetic entity separate from EMCs arising in other locations. PLAG1 gene activation appears to be involved in the development of these neoplasms.

Publication types

  • Case Reports

MeSH terms

  • Chondrosarcoma* / genetics
  • Chondrosarcoma* / metabolism
  • Chondrosarcoma* / pathology
  • DNA-Binding Proteins* / biosynthesis
  • DNA-Binding Proteins* / genetics
  • Female
  • Gene Rearrangement*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Middle Aged
  • Neoplasm Proteins* / biosynthesis
  • Neoplasm Proteins* / genetics
  • Neoplasms, Connective and Soft Tissue* / genetics
  • Neoplasms, Connective and Soft Tissue* / metabolism
  • Neoplasms, Connective and Soft Tissue* / pathology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vulvar Neoplasms* / genetics
  • Vulvar Neoplasms* / metabolism
  • Vulvar Neoplasms* / pathology

Substances

  • DNA-Binding Proteins
  • Neoplasm Proteins
  • PLAG1 protein, human

Supplementary concepts

  • Chondrosarcoma, Extraskeletal Myxoid