Revision surgery in dermatofibrosarcoma protuberans of the trunk and extremities

Dermatofibrosarcoma protuberans is a rare condition which is frequently misdiagnosed at presentation, resulting in a high incidence of local recurrence due to inadequate resection. The archives of the Department of Orthopaedics at the University of Florida were analysed to investigate the natural history and results of treatment for this tumour.

Between 1975 and 1996, 35 cases of DFSP were treated at the University of Florida. Of these, one was treated primarily, five were treated for local recurrence, 17 had tumour bed excisions following inadequate primary excisions elsewhere and 12 had tumour bed excisions following inadequate resection of local recurrences elsewhere. The data were analysed to assess the impact of age, gender, duration of symptoms, tumour site and size, surgical margin, number of operations and adjuvant treatments on survival and local recurrence outcomes.

Complete follow-up was available for 34 patients. Mean follow-up was 58 months (range 12-144 months). Thirty-three patients remain alive and disease-free. One patient died of unrelated causes. The margins obtained were wide in 28 patients, marginal in six and intralesional in one. Of the seven patients with inadequate surgical margins, four received adjuvant radiation therapy and remain disease-free. No patient with an adequate margin developed a local recurrence, but there were three local recurrences in the patients with an inadequate margin who did not receive adjuvant radiation therapy (local recurrence rate: 8%). No patient developed lymphatic or distant metastasis. Local recurrences were more likely to be classified Stage IB (17/17) than primary tumours (1/18) (P<0.001). Local recurrence was more likely where the surgical margin was less than 2.5 cm from the lesion.

Dermatofibrosarcoma protuberans is a low-grade tumour that has a high potential for local recurrence unless it can be completely excised. The overall rate of local recurrence in referred patients in this series was 20/35 cases (57%). All occurred after inadequate margins at previous surgery in other institutions. Revision surgery in these patients showed a local recurrence rate of 8%. To avoid extensive surgery for recurrences, initial treatment should be by wide excision incorporating the underlying deep fascia and a cuff of 2.5-3 cm of normal skin tissue. Radiation therapy provides a useful adjunct where adequate margins cannot be obtained.