Figure 5.

Histological findings of EWSR1::NFATC2 sarcoma. The tumors often consist of cords, nests, or pseudoacini within fibrous, hyaline, or myxoid stroma, thus closely mimicking myoepithelial tumors (a, b) or, rarely, metastatic carcinoma (c). The tumor cells are round to oval and relatively uniform with variable hyperchromasia. Diffuse sheets of small round cells, similar to Ewing sarcoma, are only uncommonly observed (d). EWSR1::NFATC2 sarcoma often variably expresses CD99, NKX2.2, and PAX7 (e), but unlike Ewing sarcoma, ~80% of EWSR1::NFATC2 sarcomas express NKX3.1 (f).