Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a rare and chronic progressive clinical entity, characterized by elevated serum IgG4 along with tissue infiltration by IgG4 + plasma cells. It is an immune-mediated fibro-inflammatory condition that can affect virtually any organ and tissue. IgG4-related lung disease (IgG4-RLD) occupies 14% of all IgG4-RD, with nonspecific symptoms and various abnormal radiographic patterns. Published data on IgG4-related hypertrophic pachymeningitis (IgG4-RHP), an increasingly recognized central nervous system manifestation of IgG4-RD, is also limited. Both lung and cranial dura involvement have not yet been reported until now. We further entail a review of the literature on the clinicopathologic features and differential diagnosis of this uncommon disease. We herein report an interesting case of a 70-year-old male patient admitted due to headache and fever. A magnetic resonance imaging (MRI) of the brain revealed extensive dural thickening with marked enhancement. Chest computed tomography (CT) scan showed nodular or mass-like consolidation and focal interstitial change. Thoracoscopic lung biopsy and lumbar puncture were conducted. After careful histopathological observation and consideration of alternative differential diagnoses, he was diagnosed with IgG4-related disease with lung and cranial dural involvement based upon significant elevation of serum and cerebrospinal fluid (CSF) IgG4 concentration. The patient was started on oral prednisolone 60 mg/day (1.0 mg/kg/day) for 14 days, and a tapering dose of 5 mg every 2 weeks followed by maintenance therapy at low dose for 3 months. His clinical manifestations, and serologic and imaging findings improved with steroid treatment. Currently, the patient remains well without disease progression. IgG4-RD should be considered as a differential when diagnosing other similar multisystemic lesions. Clinical examination, careful histological observation, and immunostaining for appropriate markers are essential in establishing the diagnosis. Clinicians should become familiar with this alternative differential diagnosis.

免疫球蛋白 (Ig) G4 相关疾病 (IgG4-RD) 是一种罕见的慢性进行性临床疾病，其特征是血清 IgG4 升高以及 IgG4 + 浆细胞的组织浸润。它是一种免疫介导的纤维炎症性疾病，几乎可以影响任何器官和组织。IgG4 相关肺病（IgG4-RLD）占所有 IgG4-RD 的 14%，具有非特异性症状和各种异常的影像学表现。已发表的关于 IgG4 相关肥厚性硬脑膜炎 (IgG4-RHP) 的数据也很有限，IgG4-RHP 是一种越来越被认可的 IgG4-RD 的中枢神经系统表现。到目前为止，尚未报道肺部和颅脑硬脑膜受累。我们进一步回顾了有关这种罕见疾病的临床病理学特征和鉴别诊断的文献。我们在此报告一个有趣的病例，一名 70 岁的男性患者因头痛和发烧入院。脑部磁共振成像 (MRI) 显示广泛的硬脑膜增厚并显着增强。胸部计算机断层扫描 (CT) 扫描显示结节或肿块样实变和局灶性间质改变。进行了胸腔镜肺活检和腰椎穿刺。在仔细组织病理学观察和考虑其他鉴别诊断后，根据血清和脑脊液 (CSF) IgG4 浓度显着升高，他被诊断为 IgG4 相关疾病，伴有肺和颅脑硬膜受累。患者开始口服泼尼松龙 60 mg/天（1.0 mg/kg/天），持续 14 天，每 2 周逐渐减量 5 mg，随后以低剂量维持治疗 3 个月。类固醇治疗后，他的临床表现、血清学和影像学表现得到改善。目前，患者身体状况良好，没有疾病进展。在诊断其他类似的多系统病变时，应将 IgG4-RD 视为鉴别诊断。临床检查、仔细的组织学观察和适当标志物的免疫染色对于确定诊断至关重要。临床医生应该熟悉这种替代性鉴别诊断。适当的标记物的免疫染色对于确定诊断至关重要。临床医生应该熟悉这种替代性鉴别诊断。适当的标记物的免疫染色对于确定诊断至关重要。临床医生应该熟悉这种替代性鉴别诊断。