Table 1.

Other types of undifferentiated small round cell sarcomas.

Entity	Genetic workup	Keratin expression
Round cell sarcomas with EWSR1-non-ETS fusions	ETS. EWSR1-NFATC2, FUS-NFATC2, and EWSR1-PATZ1 fusions [16–18]	Focal AE1/AE3 dot-like staining [19]
CIC-rearranged sarcoma (CIC-DUX4 sarcoma)	CIC-DUX4 in 95% of cases [20] Non-DUX4 partners such as NUTM1, NUTM2A, LEUTX, and FOXO4 [21–24]	Focal staining of AE1/AE3 in a small subset of cases [25]
Sarcoma with BCOR genetic alterations	BCOR-CCNB3 and BCOR-ITD [26]	Negative for AE1/AE3