恶性横纹肌样瘤 (MRT) 是一种罕见但致命的实体肿瘤，主要影响婴儿和幼儿。虽然中枢神经系统是最常见的发生部位，但肿瘤也可以在其他部位发生，包括肾脏和全身的软组织。受累的解剖部位决定了肿瘤的命名和疾病分类。虽然 MRT 和其他更常见实体的临床和影像学表现可能重叠，但存在一些特定部位的独特影像学特征。无论发生部位如何，SMARCB1 的体细胞和种系突变（很少见的 SMARCA4 突变）构成了整个横纹肌样肿瘤谱系的基础。 MRT 具有简单且非常稳定的基因组，但可以表现出相当大的分子和生物学异质性。相关肿瘤包括一类不断扩大的表型不同的实体（由 SMARC 相关改变驱动的非横纹肌样肿瘤）。 US、CT、MRI 和氟脱氧葡萄糖 PET/CT 或 PET/MRI 有助于诊断、初始分期和随访，从而为治疗决策提供信息。多灶性同步或异时性横纹肌样瘤主要发生在潜在横纹肌样瘤易感综合征（RTPS）的背景下。这些常染色体显性遗传疾病在大多数情况下由 SMARCB1（RTPS 1 型）的致病变异驱动，很少由 SMARCA4（RTPS 2 型）的致病变异驱动。基因检测和咨询对于 RTPS 至关重要。 RTPS 病例的影像学监测指南基于诊断时的年龄。 ©RSNA，2024 本文提供了补充材料。

Malignant rhabdoid tumors (MRTs) are rare but lethal solid neoplasms that overwhelmingly affect infants and young children. While the central nervous system is the most common site of occurrence, tumors can develop at other sites, including the kidneys and soft tissues throughout the body. The anatomic site of involvement dictates tumor nomenclature and nosology. While the clinical and imaging manifestations of MRTs and other more common entities may overlap, there are some site-specific distinctive imaging characteristics. Irrespective of the site of occurrence, somatic and germline mutations in SMARCB1, and rarely in SMARCA4, underlie the entire spectrum of rhabdoid tumors. MRTs have a simple and remarkably stable genome but can demonstrate considerable molecular and biologic heterogeneity. Related neoplasms encompass an expanding category of phenotypically dissimilar (nonrhabdoid tumors driven by SMARC-related alterations) entities. US, CT, MRI, and fluorodeoxyglucose PET/CT or PET/MRI facilitate diagnosis, initial staging, and follow-up, thus informing therapeutic decision making. Multifocal synchronous or metachronous rhabdoid tumors occur predominantly in the context of underlying rhabdoid tumor predisposition syndromes (RTPSs). These autosomal dominant disorders are driven in most cases by pathogenic variants in SMARCB1 (RTPS type 1) and rarely by pathogenic variants in SMARCA4 (RTPS type 2). Genetic testing and counseling are imperative in RTPS. Guidelines for imaging surveillance in cases of RTPS are based on age at diagnosis. ©RSNA, 2024 Supplemental material is available for this article.