Superficial Ewing's sarcoma family of tumors: a clinicopathological study with differential diagnoses

Background: Superficial/cutaneous Ewing’s sarcoma family of tumors (ESFT) are rare and have a relatively favorable prognosis compared with deep-seated tumors. The aim of the present study is to describe the clinicopathological characteristics of six genetically confirmed ESFT presenting a superficial location. Methods: Clinical data, radiology, histopathology, immunohistochemistry, molecular study [reverse transcriptase-polymerase chain reaction (RT-PCR)/fluorescence in situ hybridization], treatment and follow-up data were retrieved. Results: Locations included fingers (2), back (1), neck (1), thigh (1) and subcutaneous breast (1). Two tumors showed conventional morphology, one consisted of primitive neuroectodermal tumor and three tumors showed atypical vascular morphology with hemosiderin deposition and pigmentation. All cases showed CD99, FLI-1, HNK-1 and CAV-1 positivity. RT-PCR revealed the EWS/Fli1 gene fusion in all cases. Treatment was by wide excision in all cases; one received chemotherapy (CT) and one CT and radiotherapy. Available follow-up revealed the following: two patients with metastasis and death at 5 months and 2 years and one local recurrence at 18 years. Conclusions: Superficial ESFT appears to have a relatively favorable prognosis but further studies with additional series, a larger number of cases and more extensive follow-up are necessary to confirm this statement.