Effective resection of dermatofibrosarcoma protuberans using the novel Saturn's rings technique

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade sarcoma with locally infiltrative characteristics. A wide excision is made with a 5 cm gross margin. However, recently, Mohs micrographic surgery has emerged as an alternative. In this study, we evaluate a novel method (Saturn's Rings technique) for removing tumors that combines the advantages of wide excision and Mohs micrographic surgery. Between September 2001 and March 2020, 29 patients with DFSP, excluding the head and neck, were treated using Saturn's rings technique. Frozen biopsies were performed at regular intervals under various conditions and depths. If the biopsy was positive, a negative margin was obtained through an additional session. The depth and breadth of excision, reconstruction method, and postoperative recurrence were analyzed. The breadth of excision was evaluated at 1 cm intervals. Only 1 session was required in 12 cases, 2 sessions were needed in 13 cases, and 3 or more sessions were performed in 4 cases. In 24 cases, the depth of excision was limited to above the superficial fascia, with a negative biopsy of the superficial fascia. Local flaps were the most common reconstruction method (n = 21, 72.4%). No cases of recurrence were observed at follow-up (average, 45.7 months). Saturn's rings technique for DFSP maximized the preservation of normal tissue with minimal resection, was advantageous for reconstruction, and yielded good results without recurrence.