O'Driscoll Christopher J L, Dyck P James B, Spinner Robert J
Departments of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota.
Departments of Neurology, Mayo Clinic, Rochester, Minnesota.
J Neurosurg Case Lessons. 2025 Sep 1;10(9). doi: 10.3171/CASE25484.
MRI-guided targeted fascicular biopsy has been a valuable technique for diagnosing idiopathic neuropathies. It has an 80% yield and a minor permanent morbidity rate of 5%.
A 48-year-old woman with a history of localized amyloidosis to the orbital muscle 2 years earlier presented with new neurological symptoms. Extensive evaluations including skin, muscle, and distal cutaneous nerve biopsies were negative, and empirical treatment trials did not improve her condition. An MRI-guided targeted biopsy of the right ulnar nerve in the distal arm was planned. During surgery, a medial triceps branch arising from the ulnar nerve was identified and was biopsied along with a neighboring fascicle of the ulnar nerve to the flexor carpi ulnaris. The pathology of the ulnar nerve fascicle but not the contiguous triceps branch showed amyloid (AL [kappa] subtype on mass spectroscopy). The patient was started on treatment.
The positive biopsy of the ulnar nerve fascicle allowed targeted treatment of the neural amyloidosis. While the negative biopsy of the triceps branch could be attributed to sampling error, it could also be due to the fact that this branch found within the ulnar nerve is thought to originate from the radial nerve. https://thejns.org/doi/10.3171/CASE25484.
磁共振成像（MRI）引导下的靶向束状活检一直是诊断特发性神经病的一项重要技术。其活检阳性率为80%，永久性轻微发病率为5%。
一名48岁女性，2年前有眼眶肌肉局限性淀粉样变性病史，现出现新的神经症状。包括皮肤、肌肉和远端皮神经活检在内的广泛评估均为阴性，经验性治疗试验也未能改善她的病情。计划对其右臂远端的尺神经进行MRI引导下的靶向活检。手术过程中，识别出一条由尺神经发出的肱三头肌内侧支，并与尺神经至尺侧腕屈肌的相邻束状组织一起进行活检。尺神经束状组织的病理检查显示有淀粉样物质（质谱分析为AL[κ]亚型），而相邻的肱三头肌支未见异常。随后患者开始接受治疗。
尺神经束状组织活检阳性使得对神经淀粉样变性能够进行靶向治疗。肱三头肌支活检阴性可能是由于取样误差，也可能是因为这条在尺神经内发现的分支被认为起源于桡神经。https://thejns.org/doi/10.3171/CASE25484 。
