Abstract：
An emerging group of spindle cell neoplasms harboring fusions involving NTRK or non-NTRK kinase genes often share characteristic S100 and/or CD34 expression; however, the diagnostic utility of immunohistochemical stains is not well established in this family owing to their lack of specificity. Recently, CD30 expression in spindle cell neoplasms with kinase gene fusions, such as NTRK, BRAF, RAF1, and RET, has been increasingly identified. We herein report a 10-year-old girl with high-grade spindle cell sarcoma of the neck. Prior to histopathological evaluation, flow cytometry (FCM) analysis and touch smear cytology of the tumor tissue revealed CD34+ and dimCD30+ spindle cell populations. Histopathologically, the case was characterized by monomorphic spindle-shaped cytomorphology with CD30, S100, and CD34 positivity and harbored close similarities with spindle cell neoplasms with NTRK or non-NTRK gene fusions. Subsequently, a comprehensive next-generation sequencing sarcoma panel identified a rare PLEKHH2::ALK fusion, and a diagnosis of ALK-rearranged spindle cell neoplasm was made. The patient showed significant tumor response to single-agent treatment with alectinib, an ALK-tyrosine kinase inhibitor. This case supports that CD30 is expressed in an ALK-rearranged mesenchymal neoplasm. The benefit of the early detection of CD30 expression by FCM for a prompt diagnosis and treatment is highlighted in the context of an aggressive clinical course. This case represents a learning experience regarding the need to the check the status of CD30 expression in these tumors and suggests the potential clinical benefits of CD30-targeted therapy.
摘要：
一组含有涉及NTRK或非NTRK激酶基因的融合的梭形细胞肿瘤通常具有S100和/或CD34的特征性表达；然而，由于缺乏特异性，免疫组织化学染色的诊断实用性在该家族中尚未得到很好的确立。最近,CD30在具有激酶基因融合的梭形细胞肿瘤中的表达，比如NTRK,BRAF,RAF1和RET,已经越来越被识别。我们在此报告了一名10岁的女孩，患有颈部的高级梭形细胞肉瘤。在组织病理学评估之前，流式细胞术（FCM）分析和肿瘤组织的触摸涂片细胞学检查显示CD34和dimCD30梭形细胞群。组织病理学,该病例以CD30,S100和CD34阳性的梭形细胞形态为特征,与具有NTRK或非NTRK基因融合的梭形细胞肿瘤有密切的相似性.随后，一个全面的下一代测序肉瘤小组确定了一种罕见的PLEKHH2::ALK融合，并诊断为ALK重排的梭形细胞肿瘤。患者对阿来替尼单药治疗表现出明显的肿瘤反应，ALK-酪氨酸激酶抑制剂。该病例支持CD30在ALK重排的间充质肿瘤中表达。在积极的临床过程中，强调了FCM早期检测CD30表达对迅速诊断和治疗的益处。这种情况代表了关于需要检查这些肿瘤中CD30表达状态的学习经验，并暗示了CD30靶向治疗的潜在临床益处。
