A 48-year-old woman presented with a 20-year history of an asymptomatic depressed atrophic plaque on the abdomen. Five years earlier a punch biopsy of the same lesion had been carried out and a diagnosis of dermatofibroma was made. She was reassured and discharged. Further consultation was sought due to extension and thickening of the lesion. Re-examination of the initial and new incisional biopsy specimens, along with histochemical staining for CD34, established the diagnosis of atrophic dermatofibrosarcoma protuberans. A wide local excision was carried out. There has been no recurrence at 9 months of follow up.