Primary cutaneous and subcutaneous Ewing sarcoma.

BackgroundPrimary cutaneous/subcutaneous Ewing sarcoma (scEWS) is extremely rare. We describe clinical features, treatment, and outcome of this Ewing localization. ProcedureRetrospective study (1996-2012) on 56 patients. ResultsMost primary scEWS occurred in late adolescent/young adult females (F/M=1.9; median age 21.5 years), with primary tumor in the extremity/trunk (48.5%/39%). Only 35/56 samples had Real-Time-Polymerase-Chain-Reaction/Fluorescent-In-Situ-Hybridization analysis, 32/35 had EWS-translocation. Most of them exhibited known favorable prognostic factors: localized disease (54/56), initial tumor volume<200ml (51/53). Thirty and 25 patients received chemotherapy according to Euro-Ewing99 or a shorter/less intense chemotherapy regimen associated with milder toxicity. One patient had not received chemotherapy. Surgery was performed at diagnosis in 37 patients (18/37 marginal/intra-lesional resections) followed by secondary surgery in 8/37 (three remained marginal). Nineteen other patients had an initial biopsy followed by chemotherapy, 15/19 underwent late surgery (4/15 marginal/intra-lesional resections). Overall, 27/56 patients received radiotherapy. Median follow-up was six years (1-15). Two patients with metastatic disease progressed at metastatic sites. Four patients with localized disease experienced progression/relapse (local n=3, metastatic n=1). Survival was excellent: 5y-OS and 5y-EFS were 93.8% (95%CI=83-98%) and 88.5% (95%CI-=77-95), respectively. ConclusionsUnplanned primary surgery should be avoided to try to minimize potential long term sequels due to secondary surgery or radiotherapy. Biopsy with molecular analysis and staging should be performed at diagnosis to inform treatment recommendations. Patients with metastases should be treated aggressively as for other metastatic EWS. Further studies are necessary to clarify whether a less intensive chemotherapy regimen could be safely used in localized disease to minimize acute/late toxicities. Pediatr Blood Cancer 2015;62:1555-1561. (c) 2015 Wiley Periodicals, Inc.