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.
摘要：
真正的恶性混合瘤，也称为唾液腺癌肉瘤（SCS），与预后不良相关的高度侵袭性病变并不常见。这些肿瘤表现出独特的双相结构，其特征在于上皮和间质成分。最近的研究表明，大多数SCS病例源于预先存在的多形性腺瘤（PAs），暗示了逐步的发展模式。在这份报告中,我们介绍了一例73岁的女性SCS，并描述了临床，射线照相,和病理观察。值得注意的是,SCS与残留PA相关.SCS显示CTNNB1::PLAG1基因重排，为其源自PA提供了分子基础。进一步的DNA基因组分析暴露了BAP1、PER1和LRPB1中的突变。我们的发现为SCS从预先存在的PA中出现的理论提供了支持，同时强调了可能导致恶性转化的多种遗传变化。
