ESR1 and uterine carcinosarcoma: The pathological diagnosis confirmed UCS, and the epithelial component immunohistochemical results are detailed below: Estrogen receptors (ER) (+), Progesterone receptors (PR) (+), Proliferating Cell Nuclear Antigen K-67 (Ki67) (+,70%), Phosphatase and Tensin Homolog (PTEN) (-), p53 (+, wild type pattern), Paired Box 8 (Pax-8) (+, focal), Special AT-rich Sequence-binding Protein 2 (SATB2) (+), Cytokeratin Pan (CK-Pan) (+), Cytokeratin 7 (CK7) (+), Epithelial Membrane Antigen (EMA) (+), Vimentin (Vim) (+).The patient was diagnosed with uterine carcinosarcoma.