PIK3CA and ovarian carcinosarcoma: Molecular analysis using next-generation sequencing identified <i>PIK3CA</i> H1047R (c.3140A > G) and <i>CSF1R</i> (c.∗1841TG > GA) in both the epithelial and mesenchymal components, indicating a clonal origin and supporting a diagnosis of primary ovarian carcinosarcoma.