Abstract: Objective To study the clinical, neuroimaging and histopathological features of IgG4-related idiopathic hypertrophic pachymeningitis (IHP). Methods One case of pathologically confirmed IgG4-related IHP was reported, and related literature of the clinical, radiological and pathological characteristics of this disease was reviewed. Postoperative specimen was sent to Department of Pathology, Xuanwu Hospital. It was sliced and then stained with HE method and examined by immunohistochemistrical study (S-100, Ki-67, CD20, CD3, IgG, IgG4). Results The case was a 55-year-old male patient with IHP. The clinical manifestations of IHP were variable. The patient firstly presented seizures of epilepsy showing left limb convulsions. Brain contrast-enhanced MRI showed that the pachymenx was partly thickened with line-like or nodular enhancement. Microscopically, meningeal biopsies showed dura mater encephali was thickened and hardened. Under microscope, meningeal biopsies showed abnormal thickening of the pachymenx with fibrous connective tissue hyperplasia and infiltration of many inflammatory cells. Inflammatory cells were mainly composed of lymphocytes and plasmocytes with a small amount of eosinophils. Immunohistochemistrical study showed a large number of lymphocytes with expression of IgG, and a small part with expression of IgG4. The treatment of IgG4-related IHP with hormones and immunosuppressive agents was effective. Conclusion IHP is a class of unknown etiologic diseases, with dural fibrous inflammatory lesion, and part of the IHP patients may be suffering from IgG4-related IHP.

Key words: Immunoglobulin G, Meningitis, Autoimmune diseases, Immunohistochemistry

摘要： 目的 探讨IgG4 相关特发性肥厚性硬脑膜炎的临床表现、影像学及组织病理学特点。方法 回顾分析1 例IgG4 表达阳性的特发性肥厚性硬脑膜炎患者的临床表现、组织学特征，并复习相关文献。结果 男性患者，55 岁。以癫发作起病，主要表现为发作性左侧肢体抽搐。MRI 增强扫描显示局部硬脑膜增厚，并呈线样或结节样强化。大体标本观察硬脑膜明显增厚，质地坚硬；光学显微镜下可见硬脑膜异常增厚，纤维结缔组织增生及大量炎性细胞浸润，以淋巴细胞和浆细胞为主，伴少量嗜酸性粒细胞。免疫组织化学染色大量淋巴细胞表达IgG，部分表达IgG4。糖皮质激素和免疫抑制药治疗有效。结论 特发性肥厚性硬脑膜炎是一类病因不明的硬脑膜纤维性炎性病变，部分患者可能是IgG4 相关硬化性疾病谱中的一员。

关键词: 免疫球蛋白G, 脑膜炎, 自身免疫疾病, 免疫组织化学