Abstract：
COL1A1::PDGFB fusion uterine sarcoma is a rare uterine mesenchymal tumor with some clinicopathological features that overlap with those of soft tissue dermatofibrosarcoma protuberans. However, the varied clinicopathologic and genetic characteristics have not been fully revealed, which may be a potential pitfall for diagnosis. Here, we present a case of COL1A1::PDGFB fusion-positive uterine sarcoma in a 49-years-old female. Histologically, the tumor from the initial marginal excision predominantly exhibited high-grade fibrosarcomatous and myxofibrosarcoma-like appearances, while a low-grade focal area displaying storiform growth was identified in the residual tumor after subsequently extended resection. Immunohistochemically, the high-grade components mainly exhibited focal positivity for CD34 and mutated-type p53 immunoreactivity, whereas the low-grade component showed diffuse positivity for CD34 and wild-type p53 staining. The COL1A1::PDGFB fusion was confirmed by fluorescence in situ hybridization and next-generation sequencing. In addition, the TERT-124 C > T mutation was further identified in this lesion\'s fibrosarcomatous and classic storiform components. To the best of our knowledge, this is the first described case of COL1A1::PDGFB fusion uterine sarcoma with a TERT promoter mutation, which might be a novel genetic finding associated with tumorigenesis of this rare tumor.
摘要：
COL1A1::PDGFB融合子宫肉瘤是一种罕见的子宫间叶性肿瘤，其临床病理特征与软组织隆突性皮肤纤维肉瘤重叠。然而,不同的临床病理和遗传特征尚未完全揭示，这可能是诊断的潜在陷阱。这里,我们介绍了一名49岁女性COL1A1::PDGFB融合阳性子宫肉瘤。组织学上,最初边缘切除的肿瘤主要表现为高级别纤维肉瘤和粘液纤维肉瘤样表现，而在随后的扩大切除后的残留肿瘤中发现了显示出瘤样生长的低度病灶区。免疫组织化学，高级成分主要表现为CD34的局部阳性和突变型p53免疫反应性，而低级别成分显示CD34和野生型p53染色的弥漫性阳性。通过荧光原位杂交和下一代测序确认COL1A1::PDGFB融合。此外,TERT-124C>T突变在该病变的纤维肉瘤和经典骨肉瘤成分中得到进一步鉴定。据我们所知,这是第一例COL1A1::PDGFB融合子宫肉瘤具有TERT启动子突变，这可能是与这种罕见肿瘤的肿瘤发生有关的新遗传发现。
