Safety margins for dermatofibrosarcoma protuberans: a comparison between wide local excision and Mohs Tubingen technique

Background: Dermatofibrosarcoma protuberans (DFSP) is a rare, locally infiltrating, rarely metastasizing, soft tissue tumour. Due to its indistinct margins, local aggressive behaviour and high recurrence rate, the surgical approach is complex. Micrographic surgery and variants of this technique, e.g. Tubingen torte technique (TTT), should be considered as first-line treatment. Objectives: To confirm that TTT is a safe and tissue-sparing technique, relative to theoretical wide local excision (WLE), for the same lesions, as recommended by the guidelines in the literature. Materials and Methods: Seventeen patients with histologically confirmed DFSP, treated with TTT between September 2014 and February 2019, were retrospectively analysed. For each patient, the final TTT excision area was calculated and compared with the theoretical equivalent area based on WLE. The difference in area was calculated and presented as percentage difference of preserved healthy skin based on the two approaches. Results: In our patients, the mean preoperative lesion size was 4.55 ± 5.34 cm2. The mean final total excised area was 17.73 ± 11.75 cm2 for TTT and 53.65 ± 15.57 cm2 for WLE. The amount of preserved healthy tissue using the micrographic technique was significant; 69.15% (95% CI: 62.95–75.36) of healthy tissue was preserved using TTT. No recurrence or metastases were observed in any of the patients after a median follow-up period of 38.00 ± 21 months. Conclusion: In our experience, TTT remains a safe, effective and tissue-sparing treatment for DFSP patients, especially when it is essential to spare tissue and in challenging locations.