Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Turk J Pediatr. 2022;64(3):519-530. doi: 10.24953/turkjped.2021.4600.
The tumor localization/extent and imaging characteristics of rhabdomyosarcomas (RMSs) especially parameningeal type, could overlap with the common tumors of the head and neck (H&N) such as lymphoma and nasopharyngeal carcinoma (NPC). Our goal was to investigate magnetic resonance imaging (MRI) features that could favor the diagnosis of RMS over lymphoma and NPC in H&N region.
Pretreatment MRI of 42 pediatric patients (mean: 9.7±5.1 years, min-max: 2-18 years) with a recent diagnosis of RMS (n=12), lymphoma (n=14) and NPC (n=16) were retrospectively studied. Tumor localization, extension and spread were evaluated. Signal and enhancement characteristics of the tumors and the presence of necrosis were noted. ADC values were measured by using both the small sample and single slice methods. For comparison of three groups, the Kruskal Wallis test and Pairwise comparisons were used. The intra-class correlation coefficient (ICC) was calculated for the assessment of inter-observer agreement.
Nasopharynx ±parapharyngeal space involvement was detected in 58.3% of RMSs. Rhabdomyosarcoma was more heterogeneous in T2 images compared to lymphoma (p=0.014). Rhabdomyosarcoma showed significantly higher frequency of heterogeneous enhancement (p < 0.001) and necrosis (p < 0.001) among these tumors. The mean ADC values of lymphoma were significantly lower than the values of RMS (p < 0.001) and NPC (p < 0.01) for both observers. The mean ADC values were higher in RMSs than NPCs (p > 0.05). Intra-class correlation in ADC measurements was higher for the single slice method (ICC=0.997) than the small sample method (ICC=0.989).
Rhabdomyosarcoma tends to have higher ADC values than lymphoma and has a higher frequency of heterogeneous enhancement and necrotic parts than both lymphoma and nasopharyngeal carcinoma. These features could help radiologists to differentiate RMS from the above-mentioned mimickers.
横纹肌肉瘤（RMS），尤其是脑脊膜旁型，其肿瘤定位/范围和影像学特征与头颈部（H&N）的常见肿瘤，如淋巴瘤和鼻咽癌（NPC）重叠。我们的目标是研究磁共振成像（MRI）特征，这些特征可以帮助诊断 H&N 区域的 RMS 而非淋巴瘤和 NPC。
回顾性研究了 42 名儿科患者（平均年龄：9.7±5.1 岁，最小-最大：2-18 岁）的预处理 MRI，这些患者最近被诊断为 RMS（n=12）、淋巴瘤（n=14）和 NPC（n=16）。评估了肿瘤的定位、延伸和扩散。记录了肿瘤的信号和增强特征以及坏死的存在。通过小样本和单切片方法测量 ADC 值。为了比较三组，使用 Kruskal Wallis 检验和两两比较。计算了组内相关系数（ICC）以评估观察者间的一致性。
58.3%的 RMS 患者可见鼻咽部±咽旁间隙受累。与淋巴瘤相比，RMS 在 T2 图像上更不均匀（p=0.014）。RMS 显示出更高频率的不均匀增强（p<0.001）和坏死（p<0.001）。观察者测量的 ADC 值中，淋巴瘤的平均值明显低于 RMS（p<0.001）和 NPC（p<0.01）。RMS 的 ADC 值平均值高于 NPC（p>0.05）。对于单切片法（ICC=0.997）和小样本法（ICC=0.989），ADC 测量的组内相关性更高。
与淋巴瘤相比，横纹肌肉瘤的 ADC 值较高，与淋巴瘤和鼻咽癌相比，其不均匀增强和坏死部分的发生率更高。这些特征可以帮助放射科医生区分 RMS 与上述类似物。
