CD99 and neoplasm: Immunohistochemical studies showed that the tumor cells were positive for cluster of differentiation 99 (CD99) (diffuse, membranous) and friend leukemia integration 1 transcription factor (FLI1) (nuclear, weak), while they were negative for epithelial membrane antigen (EMA), Desmin, leukocyte common antigen (LCA), Sry-related HMg-Box gene 10 (SOX10), myogenin, and synaptophysin.