Kinno Ryuta, Osakabe Yuyuko, Takahashi Seiya, Kurokawa Shinji, Owan Yoshiyuki, Ono Kenjiro, Baba Yasuhiko
Department of Neurology, Showa University Fujigaoka Hospital, Fujigaoka Aoba-ku, Yokohama-shi, Kanagawa.
Division of Neurology, Department of Medicine, Showa University School of Medicine, Hatanodai Shinagawa-ku, Tokyo.
Medicine (Baltimore). 2020 Jan;99(5):e19036. doi: 10.1097/MD.0000000000019036.
Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell proliferative disorder that consistently precedes multiple myeloma. Peripheral neuropathy in patients with IgG-MGUS tends to vary in clinical phenotype. We report a rare case of a patient with IgG-MGUS who had nonsystemic vasculitic neuropathy (NSVN).
A 56-year-old Japanese woman presented with progressive sensory ataxia with episodic paresthesia. Her clinical and laboratory values were compatible with IgG-MGUS. A nerve conduction study suggested possible chronic inflammatory demyelinating polyneuropathy. However, intravenous immunoglobulin therapy was not effective. A sural nerve biopsy specimen revealed mildly reduced myelinated fiber density and myelin ovoid formation, with epineural arterioles infiltrated by inflammatory cells.
We accordingly diagnosed her condition as NSVN.
She was accordingly started on oral prednisolone (40 mg/d) at 3 months after the onset of her neurological symptoms.
At 1 year after the oral prednisolone treatment was begun, the patient's neurological symptoms showed no worsening.
These findings indicate NSVN as a possible cause of peripheral neuropathy in patients with IgG-MGUS. Cumulatively, our findings highlight the need for a nerve biopsy for peripheral neuropathy in patients with IgG-MGUS as a possible cause of NSVN. The early diagnosis of NSVN is expected to be beneficial for such patients.
意义未明的单克隆丙种球蛋白病（MGUS）是一种浆细胞增殖性疾病，始终先于多发性骨髓瘤出现。IgG型MGUS患者的周围神经病变在临床表型上往往有所不同。我们报告了一例罕见的IgG型MGUS患者，其患有非系统性血管炎性神经病变（NSVN）。
一名56岁的日本女性出现进行性感觉性共济失调并伴有发作性感觉异常。她的临床和实验室检查结果与IgG型MGUS相符。神经传导研究提示可能为慢性炎症性脱髓鞘性多发性神经病。然而，静脉注射免疫球蛋白治疗无效。腓肠神经活检标本显示有髓纤维密度轻度降低和髓鞘样小体形成，同时神经外膜小动脉有炎性细胞浸润。
因此，我们将她的病情诊断为NSVN。
在出现神经症状3个月后，她开始口服泼尼松龙（40mg/d）。
口服泼尼松龙治疗开始1年后，患者的神经症状未加重。
这些发现表明NSVN可能是IgG型MGUS患者周围神经病变的一个病因。总体而言，我们的发现强调了对于IgG型MGUS患者出现周围神经病变时进行神经活检的必要性，因为NSVN可能是其病因。NSVN的早期诊断有望对这类患者有益。
