Dermatofibrosarcoma protuberans in children and adolescents: Primary and Relapsed disease—Experience of the Cooperative Weichteilsarkomstudiengruppe (CWS)

Abstract

Background Dermatofibrosarcoma protuberans (DFSP) is a rare low‐grade tumor. Little is known about best treatment of primary and relapsed disease (RD). Methods Treatment and outcome of 40 patients with DFSP prospectively registered within the CWS‐96 and ‐2002P trials and the registry SoTiSaR (1996‐2016) were analysed. Results Median age was 8 years (range, 0.64‐17.77). Fluorescence in situ hybridization analysis to detect COL1A1‐PDGFB fusion genes was positive in 86% (12/14) of evaluated patients. Primary resection was performed in all patients. Patients had IRS group I (n = 28), II (n = 9), and III (n = 2); not available (n = 1). To achieve complete remission (CR), a secondary resection was performed in 18 patients resulting in microscopically complete (R0, n = 34/40) and microscopically incomplete (R1, n = 5/40) resection. All patients achieved CR. The 5‐year event‐free survival (EFS) and overall survival was 86% (±12; CI, 95%) and 100% (±0; CI, 95%), respectively. R0 resection/IRS I was significantly favorable for the 5‐year EFS. Local relapse occurred after a median time of 1.1 years (range, 0.04‐5.1) in 15% (6/40) after CR. All patients with RD underwent resection and achieved CR. Three patients had fibrosarcomatous DFSP, two were alive after R0 resection. Conclusion Complete surgical resection is mandatory to prevent relapse of DFSP.

Dermatofibrosarcoma protuberans in a child, that’s why soft tissue lesions are not always innocent in children

“…11 In children, the recurrence rate is approximately 9%; however, very little data exist on relapsed pediatric DFSP. 2 In our case, although the surgical resection was in healthy margins after the pathology report, we decided to remove extended tissue to reduce the recurrence rate. Moreover, we adopt a close follow-up examination period according to the literature during the first 3 years every 6 months followed by an annual follow-up because 50% of recurrences develop in the first 3 years after resection.…”

“…The wide margins in resection are important because of the recurrence rate which ranges from 26% to 60% in cases of conservative resection in contrast to wide local excision with 2‐3 cm margins from the tumor boundaries with much lower recurrence rates (0%‐30%) 11 . In children, the recurrence rate is approximately 9%; however, very little data exist on relapsed pediatric DFSP 2 . In our case, although the surgical resection was in healthy margins after the pathology report, we decided to remove extended tissue to reduce the recurrence rate.…”

“…Although often the history and physical examination findings are sufficient for the diagnosis which most of the times is a benign mass, there are cases in which the pathology results after the surgical excision are different than the expected 1 . Such a case is the one it is described below in which the surgical excision led to early diagnosis of a dermatofibrosarcoma protuberans (DFSP), a rare fibroblastic soft tissue sarcoma of low to intermediate malignancy 2 …”

“…1 Such a case is the one it is described below in which the surgical excision led to early diagnosis of a dermatofibrosarcoma protuberans (DFSP), a rare fibroblastic soft tissue sarcoma of low to intermediate malignancy. 2…”

Pediatric Pigmented Fibrosarcomatous Dermatofibrosarcoma Protuberans: Answer

“…13,14 FS-DFSP has a higher metastatic potential than ordinary DFSP; however, both often locally recur after resection. 10,15 In adults, ordinary DFSP is locally invasive, with local recurrence rate of 13.7%, and rare metastases (1.1%), whereas the fibrosarcomatous variant has a local recurrence rate of 29.8% and more common metastases (14.4%). 7 Only 12 cases of pediatric FS-DFSP have been reported in the literature, 7 with local recurrence occurring in 4 of 12 patients (33.3%), and distant metastases in 3 of 12 cases (25.0%) leading to death in 2 cases (16.5%).…”