Marek Tomas, Spinner Robert J, Carter Jodi M, Murthy Nikhil K, Amrami Kimberly K, Broski Stephen M
Department of Neurologic Surgery, Mayo Clinic, Gonda 8-214, Rochester, MN, 55905, USA.
Department of Radiology, University of Florida, Jacksonville, FL, USA.
Acta Neurochir (Wien). 2023 May;165(5):1171-1177. doi: 10.1007/s00701-023-05547-0. Epub 2023 Mar 14.
Neuromuscular choristoma (NMC) is a rare peripheral nerve lesion characterized by abnormal presence of muscle within nerve. Associated desmoid-type fibromatosis (NMC-DTF) often develops. We report F-fluorodeoxyglucose positron emission tomography (FDG PET) characteristics of NMC and NMC-DTF and propose that increased FDG activity within NMCs may be associated with subclinical NMC-DTF or NMC-DTF "precursor" tissue.
Our institutional database was searched for all NMC cases. Inclusion criteria were 1) confirmed diagnosis of NMC with or without biopsy, and 2) available PET and MRI studies. PET data included SUVmax and SUVmean of NMCs, contralateral limb normal skeletal muscle and unaffected nerves, and SUVmax of NMC-DTF if present. SUV values were compared using paired t-test. A p value of < 0.05 was considered statistically significant.
Our cohort consisted of 9 patients with NMC, 8 cases involving sciatic nerve and 1 of brachial plexus. On PET imaging, all NMC-affected nerve segments showed significantly higher FDG uptake (SUVmax/mean) compared to both contralateral normal nerve and normal skeletal muscle (all P < 0.05). Similar to sporadic DTF, NMC-DTF was highly FDG-avid (average SUVmax of 4.2). SUVmax in NMC with or without concurrent NMC-DTF did not differ (p = 0.76). Within NMC-affected nerve segment, FDG activity was relatively higher in areas with low T1/T2 MR signal.
All NMCs were more FDG avid compared to both normal skeletal muscle and contralateral unaffected nerve, arguing against the presence of heterotopic muscle in NMC as the source of FDG avidity. FDG avidity within NMC may reflect subclinical NMC-DTF or a precursor lesion, as NMC-DTF are highly FDG-avid, and the highest regions of FDG avidity in NMC occurred in regions with MR characteristics associated with NMC-DTF (i.e., lower T1/T2 signal). We believe that the integration of FDG PET with serial MR imaging in patient follow up will clarify its utility in both detection and surveillance of NMC-DTF.
神经肌肉迷离瘤（NMC）是一种罕见的周围神经病变，其特征是神经内出现异常的肌肉组织。常伴有韧带样型纤维瘤病（NMC-DTF）。我们报告了NMC和NMC-DTF的F-氟脱氧葡萄糖正电子发射断层扫描（FDG PET）特征，并提出NMC内FDG活性增加可能与亚临床NMC-DTF或NMC-DTF“前体”组织有关。
在我们机构的数据库中搜索所有NMC病例。纳入标准为：1）经活检或未经活检确诊为NMC；2）有可用的PET和MRI研究。PET数据包括NMC、对侧肢体正常骨骼肌和未受影响神经的SUVmax和SUVmean，以及若存在NMC-DTF时其SUVmax。使用配对t检验比较SUV值。p值<0.05被认为具有统计学意义。
我们的队列包括9例NMC患者，8例累及坐骨神经，1例累及臂丛神经。在PET成像中，与对侧正常神经和正常骨骼肌相比，所有受NMC影响的神经节段均显示出明显更高的FDG摄取（SUVmax/mean）（所有P<0.05）。与散发性DTF相似，NMC-DTF对FDG高度摄取（平均SUVmax为4.2）。有或无并发NMC-DTF的NMC的SUVmax无差异（p=0.76）。在受NMC影响的神经节段内，T1/T2 MR信号低的区域FDG活性相对较高。
与正常骨骼肌和对侧未受影响的神经相比，所有NMC对FDG的摄取都更高，这表明NMC中异位肌肉不是FDG摄取的来源。NMC内的FDG摄取可能反映亚临床NMC-DTF或前体病变，因为NMC-DTF对FDG高度摄取，且NMC中FDG摄取最高的区域出现在具有与NMC-DTF相关的MR特征的区域（即T1/T2信号较低）。我们认为，在患者随访中将FDG PET与系列MR成像相结合，将阐明其在NMC-DTF检测和监测中的效用。
