Management of dermatofibrosarcoma protuberans with fibrosarcomatous transformation: an evidence-based review of the literature.

Fibrosarcomatous transformation represents a rare event in dermatofibrosarcoma protuberans (DFSP) with unpredictable biological behaviour. No guidelines for the adequate treatment of patients with this rare neoplasm have been published. Herein, we present a comprehensive review of the literature comprising 157 patients with transformed DFSP focussing on surgical and adjuvant treatment modalities for this tumour. In the cohort examined, local recurrence occurred in 36% of cases and was significantly lower in patients treated by wide excision with margins ≥2 cm when compared with those treated with local excision without defined margins (P = 0.01). Consistently, negative margin status was associated with a lower recurrence rate when compared with positive or unknown margin status (P = 0.01). Distant metastases were detected in 13% of patients, which is significantly higher when compared with ordinary dermatofibrosarcoma protuberans. Systemic dissemination was preceded by local recurrence in 81% of cases, and is therefore strongly associated with tumour recurrence (P ≤ 0.001). The present data confirm that wide excision with margins ≥ 2 cm represent the gold standard in the treatment of transformed dermatofibrosarcoma protuberans, and prevents recurrence as well as metastasis. When R0-resection is not feasible, adjuvant radiation should be considered for cases with incomplete resection or unknown surgical margins. Irresectable or metastatic transformed DFSP harbouring the COL1A1-PDGFB fusion gene should be treated with imatinib in the palliative setting or as an adjunctive treatment before surgery, although responses may be short-lasting.