Fig. 3: Morphological, immunohistochemical, and FISH features of tested sarcomas.

Representative H&E pictures of tested sarcomas showing a ARMS with a PAX3-FOXO1 fusion (case no 1) showing proliferation of dyscohesive round cells with characteristic alveolar architecture (x200); b PEComa associated with a SFPQ-TFE3 fusion (case no 10). Tumor with sheet-like growth pattern. Spindle cells present clear cytoplasm and round or spindle nuclei (x200); c ASPS associated with ASPSCR1-TFE3 fusion (case no 12). Tumor shows large eosinophilic tumor cells with abundant cytoplasm arranged in compact nests (x200); d Representative picture of TFE3 immunohistochemical staining in an ASPS harboring a ASPSCR1-TFE3 fusion (case no 14). Tumor shows nuclear staining (x200); e Representative H&E pictures of CCS associated with EWSR1-ATF1 fusion (case no 25). Tumor shows plump spindle cells with pale cytoplasm arranged in solid pattern (x200); f DSRCT associated with EWSR1-WT1 fusion (case no 36). Tumor shows characteristic morphology with nests in desmoplastic stroma. Tumor cells are uniform, small, round with minimal nuclear pleomorphism. (x200); g EHE associated with WWTR1-CAMTA1 fusion (case no 58). Tumor is composed of nest and cords of epithelioid tumoral cells in sclerotic matrix (x200); h ES associated with EWSR1-FLI1 fusion (case no 71). Tumor is composed of small round cells arranged in solid pattern with occasional rosettes (x400). Insert shows nucleus with EWSR1 FISH fission; i Representative H&E of EMC with EWSR1-NR4A3 (case no 76) (x200). Spindle tumor cells with eosinophilic cytoplasm arranged in fascicles with myxoid matrix; j low grade ESS associated with JAZF1-SUZ12 fusion (case no 95). Tumor is composed of small uniform tumor cells with scant cytoplasm and oval nuclei arranged in sheets. Focal whorling of tumor cells is visible around small vessels (x200); k LGFMS/SEF associated with FUS-CREB3L2 fusion (case no 103). Bland spindle tumor cells are arranged in fascicles in myxoid matrix (x100); l BCOR-sarcoma associated with BCOR-CCNB3 fusion (case no 128), small round tumor cells are arranged in solid sheets separated by scant stroma (x200); m SFT associated with NAB2-STAT6 fusion (case no 137), hypercellular part of tumor is composed of spindle or ovoid cells admixed with hyalinized staghorn blood vessels (x200); n Representative picture of STAT6 immunohistochemical staining of SFT (case no 137). Tumor shows nuclear staining (x200); o Representative H&E picture of SS associated with SS18-SSX fusion (case no 145). This monophasic proliferation forms fascicles of monomorphic round or spindle cells (X200).