Sarcome d'Ewing cutané primitif : difficultés diagnostiques et thérapeutiques

Cutaneous Ewing's sarcoma raises concerns about diagnosis and treatment. Owing to the non-specificity of its clinical presentation, histology and immunoprofile, diagnosis of superficial Ewing's sarcoma is difficult and numerous differential diagnoses must be considered. When dealing with a surface tumour, the diagnosis of cutaneous Ewing's sarcoma must be considered. CD99 immunostaining and molecular testing for evidence of EWSR1 rearrangement are useful investigations to confirm the diagnosis. Furthermore, modalities of treatment must be carefully discussed. Cutaneous Ewing's sarcoma is currently treated in the same way as osseous Ewing's sarcoma (wide surgical excision, adjuvant radiotherapy when surgical margins are unsatisfactory, systemic adjuvant chemotherapy, and, in some cases, bone marrow transplant). However, some studies show a more favourable prognosis for cutaneous Ewing's sarcoma than for osseous Ewing's sarcoma. We may thus ask whether such aggressive multimodal treatment is needed.