Primary vulvar Ewing sarcoma/peripheral primitive neuroectodermal tumor with pelvic lymph nodes metastasis: A case report and review of literature.

Ewing sarcoma (ES) and peripheral primitive neuroectodermal tumors (pPNET) are soft tissue tumors that generally affect the bones. Extraosseous ES/pPNET has been rarely reported. Our patient presented with a 6 × 4 cm right subcutaneous solid vulvar lesion causing pain and discomfort. Pathology and immunohistochemistry staining showed strong positivity for CD99 and vimentin, favoring the diagnosis of ES/pPNET. Magnetic resonance imaging showed a 6-cm lesion in the right vulvar region with enlarged bilateral inguinal and right iliac lymph nodes. Fluorescence in situ hybridization test for translocation t(11;22)(q24;q12) was positive, confirming the diagnosis. The patient received three cycles of neoadjuvant chemotherapy with vincristine, adriamycin, cyclophosphamide alternating with ifosfamide and etoposide with complete response. The patient underwent vulvar radical local excision. Residual tumor measured 1.6 cm with free margins. She received four additional cycles of adjuvant chemotherapy and 30 sessions radiotherapy. She is currently disease free after 37 months. No ES/pPNET cases with pelvic lymph nodes metastasis were ever reported.