Hospital Italiano de Buenos Aires.
Rev Fac Cien Med Univ Nac Cordoba. 2023 Mar 31;80(1):66-69. doi: 10.31053/1853.0605.v80.n1.34753.
IgG4 related disease (IgG4-RTD) is an infrequent disease with possible multiple organ involvement. It is characteristic to find inflammatory nodules with IgG4 positive plasma cell infiltration, storiform fibrosis and obliterative phlebitis. We present a patient with an inflammatory pseudotumor in the right upper lobe, mimicking a primary lung tumor.
Our patient, a 48-year old heavy smoker (25 pack/year) with no relevant medical background, referred chest pain, non-productive cough and sporadic nightly fever. Image findings revealed a mass in the right upper lobe, with increased SUV in PET-scan, and mediastinal lymphadenopathies. Primary lung tumor was suspected and right upper lobectomy was performed. Due to absence of cellular atypia and the intense plasmacytic activity in the lesion, immunohistochemical analysis was performed: abundant IgG4 plasma cells were identified, with a IgG4/IgG relation of 74%. Diagnosis of IgG4- inflammatory pseudotumor was made.
After an extensive bibliographic review, we found just one similar case reported with an IgG4-lung pseudotumor without systemic disease. Due to the broad spectrum of clinical features of IgG4-RTD, and the potential multiple organ involvement, it is hard to find a classification and diagnostic criteria with high sensitivity and specificity, nevertheless they can be useful in clinical practice.
There are several benign inflammatory diseases which can mimic a primary lung tumor. Although incidence is low, IgG4 pseudotumor should be considered as a differential diagnosis in the absence of malignancy.
IgG4 相关疾病（IgG4-RTD）是一种罕见的疾病，可能涉及多个器官。其特征是发现炎症性结节，伴有 IgG4 阳性浆细胞浸润、席纹状纤维化和闭塞性静脉炎。我们报告了 1 例右上叶炎性假瘤患者，其表现类似于原发性肺肿瘤。
我们的患者为 48 岁重度吸烟者（25 包/年），无相关病史。患者出现胸痛、干咳和间歇性夜间发热。影像学检查发现右上叶肿块，PET 扫描 SUV 升高，纵隔淋巴结肿大。怀疑为原发性肺肿瘤，行右上肺叶切除术。由于病变无细胞异型性和强烈的浆细胞活性，进行了免疫组化分析：大量 IgG4 浆细胞被识别，IgG4/IgG 比值为 74%。诊断为 IgG4-炎性假瘤。
在广泛的文献回顾后，我们仅发现 1 例类似的 IgG4-肺部假瘤病例，无系统性疾病。由于 IgG4-RTD 的临床表现广泛，且可能涉及多个器官，因此难以找到具有高敏感性和特异性的分类和诊断标准，但这些标准在临床实践中可能有用。
有几种良性炎症性疾病可模拟原发性肺肿瘤。尽管发病率较低，但在没有恶性肿瘤的情况下，应考虑 IgG4 假瘤作为鉴别诊断。
