Institut de Pathologie Multisite, Site Est, Hospices Civils de Lyon, Lyon, France.
Department of Biopathology, UNICANCER, Centre Leon Bérard, Lyon, France.
Virchows Arch. 2022 Oct;481(4):665-669. doi: 10.1007/s00428-022-03335-2. Epub 2022 May 9.
Ewing sarcoma (ES) is a highly malignant round cell sarcoma, characterized by gene fusion involving FET (FUS, EWSR1, TAF15) and ETS family genes, respectively. The involvement of the EWSR1 gene has been reported in approximately 90% of cases of ES, with the EWSR1::FLI1 fusion being the most frequent. We report the case of a newborn with a localized soft tissue paravertebral neoplasm diagnosed prenatally. Histopathology and immunophenotype were consistent with a CD99 + , NKX2.2 + undifferentiated round cell sarcoma (URSC); whole-exome RNA-sequencing demonstrated an undescribed in-frame TAF15::ETV4 fusion transcript, while consensus clustering analysis showed high transcriptomic proximity to the ES group. Given clinical context, high tumor chemosensitivity to ES conventional drugs, morphological characteristics, nature of the fusion partners involved, and high transcriptomic proximity to bona fide ESs, this case may represent a new genetic variant of ES.
尤因肉瘤（ES）是一种高度恶性的圆形细胞肉瘤，其特征在于分别涉及 FET（FUS、EWSR1、TAF15）和 ETS 家族基因的基因融合。大约 90%的 ES 病例中都有 EWSR1 基因的参与，其中最常见的是 EWSR1::FLI1 融合。我们报告了一例产前诊断为局限性椎旁软组织肿瘤的新生儿病例。组织病理学和免疫表型与 CD99+、NKX2.2+未分化圆形细胞肉瘤（URSC）一致；全外显子 RNA 测序显示存在未描述的 TAF15::ETV4 融合转录本，而共识聚类分析显示与 ES 组具有高度转录组相似性。鉴于临床背景、对 ES 常规药物的高肿瘤化疗敏感性、形态学特征、涉及的融合伙伴的性质以及与真正的 ES 的高转录组相似性，该病例可能代表 ES 的一种新的遗传变异。
