Intraarticular synovial sarcoma of the knee rising from a lateral meniscus - a case report

Orthop Traumatol Surg Res. 2018 Apr;104(2):227-230. doi: 10.1016/j.otsr.2018.01.002. Epub 2018 Feb 21.

Abstract

Synovial sarcoma (SS) is a rare mesenchymal tumor, accounting less than 10% of soft tissue sarcomas. We report a case of intraarticular SS mimicking nodular synovitis and lateral meniscus rupture. Due to clinical and radiological presentation, arthroscopic synovectomy was performed, and histology confirmed nodular synovitis. After four years the lesion recurred and new arthroscopic biopsy was performed, revealing a monophasic SS with SYT/SSX1 translocation. Repeated histology of the first specimen confirmed appearance of a nodular synovitis microscopically, with no morphological criteria for a sarcoma, but molecular analysis showed positive SYT/SSX1 translocation. Wide extraarticular knee resection and reconstruction with a tumor megaendoprosthesis-allograft composite was performed with a negative tumor margins. This case report showed that in a case of benign histological appearance, underlying sarcoma is possible and could be identified in early stages only with an advanced pathology methods.

Level of evidence: Level IV historical case.

Keywords: Arthroscopy; Diagnostic molecular pathology; Knee prosthesis; Synovial sarcoma.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Genetic Testing
  • Humans
  • Knee Joint
  • Male
  • Menisci, Tibial
  • Neoplasm Recurrence, Local / genetics*
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / surgery*
  • Oncogene Proteins, Fusion / genetics*
  • Sarcoma, Synovial / genetics*
  • Sarcoma, Synovial / pathology
  • Sarcoma, Synovial / surgery*
  • Soft Tissue Neoplasms / genetics*
  • Soft Tissue Neoplasms / pathology
  • Soft Tissue Neoplasms / surgery*

Substances

  • Oncogene Proteins, Fusion
  • SYT-SSX fusion protein