Immunohistochemistry revealed the neoplastic cells expressing Vimentin, Mic-2, Bcl-2 and are negative for Myf-4, S-100, CK-7, CK-20, SMA, Desmin HMB-45, supporting diagnosis of poorly differentiated small cell variant synovial sarcoma (Figure 8). This evidence concerns the gene CD99 and synovial sarcoma.