{Reference Type}: Case Reports {Title}: Salivary gland carcinosarcoma ex pleomorphic adenoma: a case report with molecular characterization. {Author}: Javaid S;Wang D;Kelly BJ;Kalim S;Yanich J;Kalmar JR;Mallery SR; {Journal}: Oral Surg Oral Med Oral Pathol Oral Radiol {Volume}: 138 {Issue}: 2 {Year}: 2024 08 11 暂无{DOI}: 10.1016/j.oooo.2024.02.030 {Abstract}: True malignant mixed tumors, also known as salivary gland carcinosarcoma (SCS), are uncommon yet highly aggressive lesions associated with a poor prognosis. These tumors exhibit a distinctive biphasic structure characterized by both epithelial and mesenchymal components. Recent research has shown that the majority of SCS cases stem from pre-existing pleomorphic adenomas (PAs), suggesting a stepwise developmental pattern. In this report, we present a case of a 73-year-old female with SCS and describe the clinical, radiographic, and pathologic observations. Notably, the SCS was associated with a residual PA. The SCS displayed a CTNNB1::PLAG1 gene rearrangement, providing a molecular basis for its origin from the PA. Further DNA genomic analysis exposed mutations in BAP1, PER1, and LRPB1. Our findings provide support to the theory that SCS emerges from a pre-existing PA while highlighting the multiple genetic changes that could contribute to malignant transformation.