Division of Neuromuscular Medicine, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
Division of Neurology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Eur J Neurol. 2023 Oct;30(10):3404-3406. doi: 10.1111/ene.16008. Epub 2023 Aug 11.
Myopathies associated with monoclonal gammopathy are relatively uncommon and underrecognized, treatable myopathies, and include sporadic late onset nemaline myopathy, light chain amyloid myopathy, and a recently described vacuolar myopathy with monoclonal gammopathy and stiffness (VAMGS). Herein, we report a new subtype of monoclonal gammopathy-associated myopathy (MGAM) in a polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (POEMS) patient.
Case report.
A 51-year-old woman presented with a 6-month history of progressive bilateral foot drop, lower limb edema, and a 15-lb weight loss. She denied muscle stiffness. Neurologic exam showed severe distal weakness, mild proximal weakness, and length-dependent sensory deficits. Laboratory studies revealed biclonal gammopathy (IgG kappa and IgA lambda), thrombocytosis, and elevated vascular endothelial growth factor. Creatine kinase was normal. Electrodiagnostic studies identified mixed demyelinating and axonal polyradiculoneuropathy and a superimposed proximal myopathy. Gluteus medius biopsy demonstrated scattered fibers with glycogen-filled vacuoles, similar to VAMGS, with additional rare myofibers containing polyglucosan bodies. She was diagnosed with POEMS syndrome and concomitant glycogen storage myopathy. Next-generation sequencing of glycogen storage and polyglucosan body myopathy-related genes was unrevealing. Proximal weakness resolved after autologous stem cell transplant.
This patient expands a spectrum of MGAM. Recognition of this condition and other subtypes of MGAM is of utmost important because they are treatable.
与单克隆丙种球蛋白病相关的肌病较为罕见且未被充分认识，但却是可治疗的肌病，包括散发性迟发性杆状体肌病、轻链淀粉样变性肌病，以及最近描述的伴有单克隆丙种球蛋白病和僵硬的空泡性肌病（VAMGS）。在此，我们报告了一例多发性神经病、器官肿大、内分泌病、M 蛋白和皮肤改变（POEMS）患者中一种新的单克隆丙种球蛋白病相关肌病（MGAM）亚型。
病例报告。
一名 51 岁女性，表现为进行性双侧足下垂、下肢水肿和 15 磅体重减轻，病程 6 个月。她否认肌肉僵硬。神经检查显示严重的远端无力、轻度的近端无力和长度依赖性感觉缺失。实验室研究显示双克隆丙种球蛋白（IgG κ和 IgA λ）、血小板增多和血管内皮生长因子升高。肌酸激酶正常。电诊断研究发现混合脱髓鞘和轴索性多发性神经病，并伴有重叠的近端肌病。臀中肌活检显示散在纤维伴糖原填充空泡，类似于 VAMGS，伴有额外的罕见肌纤维含有多葡聚糖体。她被诊断为 POEMS 综合征和伴发性糖原贮积肌病。糖原贮积和多葡聚糖体肌病相关基因的下一代测序无结果。自体干细胞移植后近端无力缓解。
该患者扩展了 MGAM 的范围。认识到这种情况和其他类型的 MGAM 非常重要，因为它们是可治疗的。
