Fli1 [86] and ERG [87] reactivity are seen in cases with the respective fusions. A subtype of ES, adamantinoma-like Ewing sarcoma (ALES) tends to show a nested/lobular architecture, peripheral palisading, hyalinized stroma, and abrupt squamous differentiation; IHC evidence of squamous differentiation in the form of diffuse cytokeratin and p40/p63 reactivity is noted along with CD99 and NKX2.2 and most commonly the EWSR1::FLI1 fusion [88, 89]. This evidence concerns the gene CD99 and Ewing sarcoma.