No abstract

Background: Dermatofibrosarcoma protuberans (DFSP) is a potentially malignant soft tissue tumor that if not accurately diagnosed and managed, has a high recurrence rate. Case presentation: A 35 years old man presented with 5 years history of slowly enlarging, initially painless anterior abdominal wall mass. He had a similar mass at the same location 10 years ago that was excised and diagnosed as a benign fibrous neoplasm. CT scan revealed a soft tissue density well-circumscribed mass that blended with the surrounding soft tissues. Excision was done and histology revealed dermatofibrosarcoma protuberans with atrophy of the overlying skin, positive margins, and areas of fibrosarcomatous change. The tumor was positive for Vimentin and negative for erythroblastosis transcription variant related gene (ERG) and S100. A repeat excision was advised until clear margins were achieved. Conclusion: Tumor size and herringbone growth pattern do not necessarily imply fibrosarcomatous transformation. Also, accurate diagnosis is key in preventing the recurrence of DFSP. Pathologists need to be aware of such rare cancers since they can easily be missed.