SSX4 and fibrosarcoma: Known and/or expected genetic alterations that are pathognomonic for the different diseases were frequently identified: FUS-DDIT3 (myxoid liposarcoma), ETV6-NTRK3 (infantile fibrosarcoma), SS18-SSX2 and SS18-SSX4 (synovial sarcoma), SMARCB1 mutation (soft tissue rhabdoid tumor), EWSR1-CREB1 (angiomatoid fibrous histiocytoma), BCOR-CCNB3 (small cell sarcoma), and NAB2-STAT6 (solitary fibrous tumor) (Figure 3).