[Perianal dermatofibrosarcoma protuberans: a case report, review and update].

Dermatofibrosarcoma protuberans is a low-grade sarcoma typically originating in the dermis but with local invasion of subcutaneous cell and muscle tissue. We report a case of perianal dermatofibrosarcoma protuberans in a 41-year-old male complaining of anal pain and constipation. To date, only two cases of perianal dermatofibrosarcoma protuberans have been reported. The unusual location hinders surgical treatment. The characteristic translocation t(17;22)(q22;q13) leading to the formation of COL1A1/PDGFβ fusion transcripts is not only of diagnostic value but also enables an alternative imatinib-based therapy in inoperable or metastatic cases. The pertinent literature is reviewed.