Dermatofibrosarcoma protuberans: pathology, genetics, and potential therapeutic strategies.

Dermatofibrosarcoma protuberans (DFSP), the most common dermal sarcoma, is a malignant fibroblastic tumor most frequently arising in middle-aged adults. It is typically a low-grade sarcoma that grows slowly but has a high rate of local recurrence with low metastatic potential. Dermatofibrosarcoma protuberans is characterized by a specific translocation t(17;22)(q22;q13) leading to the formation of COL1A1-PDGFB fusion transcripts. Histologically, DFSP has characteristic morphology, of storiform islands of bland spindle cells, and immunohistochemically, it shows diffuse expression of CD34. However, the morphology and immunoprofile can overlap with a variety of other soft tissue neoplasms. The preferred management of localized disease is wide surgical resection or Mohs micrographic surgery, whereas radiotherapy may be used for margin-positive disease where reexcision is not possible, or for inoperable disease. Dermatofibrosarcoma protuberans is generally regarded as refractory to conventional chemotherapy. Treatment options for systemic disease have been previously limited, but the PDGFβR, KIT, and ABL inhibitor imatinib is now an option for effective systemic therapy. Continued insight into the tumorigenic molecular changes generated by the fusion oncogene may lead to further specific targeted treatments. We review DFSP, discussing the morphologic spectrum and variants, immunohistochemistry, molecular genetic findings, potential targeted treatments, and the differential diagnosis.