Cytogenetically, all SS variants are characterized by the reciprocal translocation t(X;18)(p11.2;q11.2), which leads, at molecular level, to the fusion between the synovial sarcoma translocation gene on chromosome 18 (SS18) and one of the synovial sarcoma X breakpoint (SSX) genes on chromosome X: SSX1, SSX2 and rarely with SSX4 [36-38]. Here, SSX4 is linked to synovial sarcoma.