Synovial Sarcoma


Synovial sarcomas are the fourth most common sarcoma and can occur at any age. The tumours usually present as a slow growing, painful mass and occur commonly in the deep soft tissue of the lower and upper extremities and can occur in the trunk, head, and neck region.

At least 95% of cases harbour a t(X;18)(p11;q11) that results in the fusion of SS18 on chromosome 18 with one of three different genes on the X chromosome: SSX1, SSX2, or SSX4.  There is conflicting data in the literature on the prognostic differences between the various SSX fusion partners.  The function of the resulting fusion protein is unknown.


  • Completed CGL Cytogenetics Solid Tumour Testing requisition form
  • FFPE Tumour specimen (see Specimen GuidelinesCytogenetics FISH FFPE test type)
    • An H&E stained slide with the tumour region circled, and the estimated % tumour content written in the Tumour Content field of the requisition.  NOTE: A minimum of 10% tumour and at least 200 nuclei is required.
    • Specimen block and/or at least one unstained slide for each probe requested.


Results are reported within fourteen days from receipt of specimen and completed requisition form.  


  • Specimens are reported as Positive for a rearrangement, Negative for a rearrangement.
  • 95% of synovial sarcomas have an SS18 rearrangement, and the remaining 5% of cases have a variant translocation, insertion, or complex karyotype that may not be detected with this assay.
  • SS18 rearrangements are not commonly identified in other types of sarcomas.


FISH analysis is performed on the provided paraffin embedded tissue using the SS18 (18q11.2) dual-colour, break-apart probe (Vysis).


  1. Terry et al Diagn Mol Pathol (2005) PMID: 15905690
  2. Kubo et al Springerplus (2015) PMID: 26217552
  3. Nielsen et al Cancer Discov (2015) PMID: 25614489
  4. Ladanyi et al Cancer Res (2002) PMID:11782370
  5. Guillou el al J Clin Oncol (2004) PMID: 15364967