Five patients were initially diagnosed as having undifferentiated uterine sarcoma with nuclear uniformity, GREB1-rearranged sarcoma, atypical mesenchymal tumor, and sarcoma, not otherwise classifiable (cases 1, 2, 3, 4, and 6, respectively) (Table 1). The gene discussed is GREB1; the disease is mesenchymal cell neoplasm.