Sidorov I V, Fedorova A S, Sharlai A S, Konovalov D M
Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia.
Lomonosov Moscow State University, Moscow, Russia.
Arkh Patol. 2023;85(5):13-21. doi: 10.17116/patol20238505113.
The group of undifferentiated round cell sarcomas, according to the World Health Organization Classification, in addition to Ewing's sarcoma (ES), includes round cell sarcoma with rearrangement of the gene with partners not from the ETS gene family, sarcoma with gene alterations, -rearranged sarcoma. Despite the fact that all tumors have clear histological and immunological criteria, their diagnosis can be difficult, given the fact that there are overlapping variants of the morphological picture and immunophenotype both within the group and with other round cell tumors.
Present a comparative analysis of genetically verified ES, sarcoma with gene alterations and -rearranged sarcoma.
A comparative study of biopsy specimens of bones, soft tissues and internal organs was carried out in 118 patients with ES, 10 with gene alterations and 8 with rearranged sarcomas. All cases were genetically verified. The following research methods were used: histological, immunohistochemical, RT-PCR, RNA sequencing and FISH.
Within our cohort, it was shown that ES predominantly affects bones, while soft tissue localization is more typical for the other two undifferentiated round cell sarcomas. Histologically, in the overwhelming majority of cases, ES is characterized by a monomorphic round-cell structure; on the contrary, heterogeneous structure is typical for sarcoma with alterations of the gene, -rearranged sarcoma. High sensitivity and specificity of CD99/NKX2.2 co-expression for ES, BCOR/SATB2/TLE1 for sarcoma with gene alterations, high specificity and low sensitivity of WT1/ETV4 co-expression for -rearranged sarcoma was shown.
For the differential diagnosis of undifferentiated round-cell sarcomas, it is necessary to take into account the clinical, morphology when compared with the data of the IHC study, and verification by molecular genetic methods is necessary to improve the accuracy of diagnosis.
根据世界卫生组织分类，未分化圆形细胞肉瘤组，除了尤因肉瘤（ES）外，还包括与非ETS基因家族伙伴发生基因重排的圆形细胞肉瘤、伴有基因改变的肉瘤、重排肉瘤。尽管所有肿瘤都有明确的组织学和免疫学标准，但鉴于该组内以及与其他圆形细胞肿瘤存在形态学图像和免疫表型的重叠变体，其诊断可能会很困难。
对经基因验证的ES、伴有基因改变的肉瘤和重排肉瘤进行比较分析。
对118例ES患者、10例伴有基因改变的患者和8例重排肉瘤患者的骨骼、软组织和内脏活检标本进行了比较研究。所有病例均经基因验证。采用了以下研究方法：组织学、免疫组织化学、逆转录聚合酶链反应（RT-PCR）、RNA测序和荧光原位杂交（FISH）。
在我们的队列中，结果显示ES主要累及骨骼，而软组织定位在其他两种未分化圆形细胞肉瘤中更为典型。组织学上，在绝大多数病例中，ES的特征是单形性圆形细胞结构；相反，伴有基因改变的肉瘤、重排肉瘤的典型特征是异质性结构。结果显示，CD99/NKX2.2共表达对ES具有高敏感性和特异性，BCOR/SATB2/TLE1对伴有基因改变的肉瘤具有高敏感性和特异性，WT1/ETV4共表达对重排肉瘤具有高特异性和低敏感性。
对于未分化圆形细胞肉瘤的鉴别诊断，与免疫组化研究数据相比，有必要考虑临床、形态学因素，并且为了提高诊断准确性，分子遗传学方法验证是必要的。
