EFT cells show membranous expression of CD99 or MIC2 on immunohistochemistry [Figure 2].9 Antibody against FLI1, which is centered in the nucleus of the tumor cells [Figure 2], has been shown to be specific for EFT.10 Depending on the degree of neuroectodermal differentiation, the tumor cells may also express neuron-specific enolase (NSE), synaptophysin, and S-100 protein. This evidence concerns the gene CD99 and neoplasm.