Extraosseous Ewings Sarcoma-Primitive Neuroepithelial Tumor, also known as extraosseous ewings sarcoma-primitive neuroepithelial tumour, is related to extraosseous ewing sarcoma and ewing sarcoma, and has symptoms including fever An important gene associated with Extraosseous Ewings Sarcoma-Primitive Neuroepithelial Tumor is CD99 (CD99 Molecule (Xg Blood Group)).