label: Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor of Bone
label_lc: ewing sarcoma/peripheral primitive neuroectodermal tumor of bone
description: A spectrum of malignant tumors arising from the bone and characterized morphologically by the presence of small round cells.  Ewing sarcoma and peripheral primitive neuroectodermal tumor represent the ends of a spectrum, with Ewing sarcoma lacking evidence of neural differentiation and the markers that characterize the peripheral primitive neuroectodermal tumor.  Ewing sarcoma and peripheral primitive neuroectodermal tumor may share cytogenetic abnormalities, proto-oncogene expression, cell culture and immunohistochemical abnormalities.  Pain and the presence of a mass are the most common clinical symptoms.