The CIC-DUX4 translocation is the most common genetic alteration of small round cell sarcomas without EWSR1 rearrangement. These “Ewing-like sarcomas” usually occur in peripheral soft tissues, and rare primary central nervous system (CNS) tumors have been described. We report a rare case of primary spinal intramedullary Ewing-like sarcoma harboring CIC-DUX4 translocation. A 23-year-old man presented with weakness in the extremities. Magnetic resonance imaging revealed a large intramedullary tumor spanning C3–C5 with heterogeneous enhancement following gadolinium administration. Histologically, most of the tumor displayed dense myeloid proliferation composed of medium- to slightly small-sized primitive cells. Postoperatively, he received local adjuvant radiation therapy without tumor progression for 10 months. Target RNA sequencing analysis revealed the CIC-DUX4 fusion gene. Methylation array analysis resulted in a diagnosis of “methylation class CNS Ewing sarcoma family tumor with CIC alteration”. Although this tumor lacked characteristic histological features such as lobular structures in association with desmoplastic stroma, relatively uniform nuclei with prominent nucleoli and eosinophilic cytoplasm, which are often found in CIC-rearranged sarcomas of soft tissue, were identified. Recently, many CNS and soft tissue tumors require genetic analysis for precise diagnosis. To consider certain molecular testing, careful histological examination is essential.

中文翻译：

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携带CIC-DUX4易位的原发性脊髓髓样尤文样肉瘤：类似于其软组织对应物的细胞学外观，但没有叶，与增生基质相关。

该CIC - DUX4易位的小圆细胞肉瘤最常见的遗传改变而不EWSR1重排。这些“尤文氏肉瘤”通常发生在周围的软组织中，并且已经描述了罕见的原发性中枢神经系统（CNS）肿瘤。我们报道了罕见的原发性脊柱内髓样尤文样肉瘤，带有CIC - DUX4易位。一名23岁的男子四肢无力。磁共振成像显示，administration给药后，一个大的髓内肿瘤跨度为C3–C5，异质性增强。从组织学上讲，大多数肿瘤显示出由中等至略小尺寸的原始细胞组成的致密髓样增生。术后，他接受了局部辅助放疗，没有肿瘤进展10个月。靶RNA测序分析揭示了CIC - DUX4融合基因。甲基化阵列分析结果诊断为“ CIC甲基化类中枢神经系统尤因肉瘤家族肿瘤”改造”。尽管该肿瘤缺乏特征性组织学特征，例如与增生基质相关的小叶结构，但已鉴定出相对较均匀的核，具有突出的核仁和嗜酸性细胞质，通常在软组织的CIC重排肉瘤中发现。最近，许多中枢神经系统和软组织肿瘤需要进行基因分析以进行精确诊断。要考虑某些分子检测，仔细的组织学检查至关重要。