Surgical margins for excision of dermatofibrosarcoma protuberans

Background: Dermatofibrosarcoma protuberans (DFSP) commonly recurs after standard surgical excision with a wide margin. No studies have been undertaken to objectively determine the appropriate surgical margins by measuring the extension of the subclinical tumor. Objective: Our purpose was to measure the subclinical extent of tumor in 20 patients with DFSP to determine appropriate surgical margins. Methods: We mapped the subclinical tumor extension with Mohs micrographic surgery and measured the surgical margins required to clear the tumor completely. Results: We found that a 2.5 cm surgical margin through the deep fascia (nonscalp) or periosteum (scalp) cleared all of the tumors. DFSP tumors that measured less than 2 cm were completely cleared with a 1.5 cm surgical margin. None of our patients had a recurrence of the tumor, and in 16 of 20 patients primary repairs were possible. Conclusion: Our data support the use of Mohs surgery to excise DFSP with maximum conservation of tissue and a high cure rate.