Dermatofibrosarcoma Protuberans Masquerading as a Benign Scar on the Shoulder of a Caucasian Female

We report the case of a 62-year-old Caucasian female with an 11-year history of an asymptomatic and unchanging plaque on her left shoulder. Physical examination revealed a 2.5cm round atrophic plaque with slight central nodularity and telangiectasias overlying a light-brown pigment network. The lesion was clinically most consistent with a scar from a prior surgical procedure. However, as there was no history of prior trauma at the site, a punch biopsy of the lesion was performed. Histopathological findings were suggestive of a neurofibroma, however, the possibility of a dermatofibrosarcoma protuberans was also considered. Immunohistochemical staining was performed which was negative for S100 and positive for CD34, consistent with DFSP. A larger repeat biopsy was then obtained, revealing findings consistent with dermatofibrosarcoma protuberans (DFSP). Fluorescence in situ hybridization (FISH) showed a PDGFB/COL1A1 fusion gene, confirming the diagnosis of DFSP. For patient tolerability, the sarcoma was completely excised via wide local excision under general anesthesia.