Expression of synaptophysin and neurofilament protein confirms predominantly neuroblastic differentiation of primitive neuroectodermal tumors (PNET).

We report here that neuronal and glial differentiation is easily detected using synaptophysin (SF) and neurofilament protein (NFP) immunohistochemistry in primitive neuroectodermal tumors (PNET). Thus, for all practical reasons, every PNET should be regarded as PNET with "hidden" multipotential or bipotential differentiation.