Dermatofibrosarcoma protuberens (DFSP)


Dermatofibrosarcoma protuberans are one of the most common dermal sarcomas and are superficial but locally aggressive tumours. They primarily occur in young to middle aged adults, although they can be seen in children.

Most, if not all, DFSP harbour a rearrangement of COL1A1 (17q21) and PDGFB (22q13).  This fusion is usually present as a supernumerary ring chromosome, although some are due to a simple translocation. PDGFB is a growth factor that comes under the control of the COL1A1 promoter leading to increased expression of PDGFB which stimulates tumour growth via the PDGFB receptor. Some of these tumours respond to imatinib treatment.


  • 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, or Negative for a rearrangement – extra signals.


FISH analysis is performed on the provided paraffin embedded tissue using a dual colour, break-apart probe (Empire Genomics) to PDGFB (22q13).


  1. Karanian et al. Mod Pathol (2015) PMID: 25081750
  2. Ha et al. Hum Pathol (2013) PMID: 23347652
  3. Salgado et al. Genes Chromosomes Cancer (2011)  PMID: 21484928  
  4. Patel et al Hum Pathol (2008) PMID: 17950782
  5. McArthur et al. J Clin Oncol (2005) PMID: 15681532