Objective: To investigate the value of plasma cells for diagnosing lymph node diseases. Methods: Common lymphadenopathy (except plasma cell neoplasms) diagnosed from September 2012 to August 2022 were selected from the pathological records of Changhai Hospital, Shanghai, China. Morphological and immunohistochemical features were analyzed to examine the infiltration pattern, clonality, and IgG and IgG4 expression of plasma cells in these lymphadenopathies, and to summarize the differential diagnoses of plasma cell infiltration in common lymphadenopathies. Results: A total of 236 cases of lymphadenopathies with various degrees of plasma cell infiltration were included in the study. There were 58 cases of Castleman's disease, 55 cases of IgG4-related lymphadenopathy, 14 cases of syphilitic lymphadenitis, 2 cases of rheumatoid lymphadenitis, 18 cases of Rosai-Dorfman disease, 23 cases of Kimura's disease, 13 cases of dermal lymphadenitis and 53 cases of angioimmunoblastic T-cell lymphoma (AITL). The main features of these lymphadenopathies were lymph node enlargement with various degrees of plasm cell infiltration. A panel of immunohistochemical antibodies were used to examine the distribution of plasma cells and the expression of IgG and IgG4. The presence of lymph node architecture could help determine benign and malignant lesions. The preliminary classification of these lymphadenopathies was based on the infiltration features of plasma cells. The evaluation of IgG and IgG4 as a routine means could exclude the lymph nodes involvement of IgG4-related dieases (IgG4-RD), and whether it was accompanied by autoimmune diseases or multiple-organ diseases, which were of critical evidence for the differential diagnosis. For common lesions of lymphadenopathies, such as Castleman's disease, Kimura's disease, Rosai-Dorfman's disease and dermal lymphadenitis, the expression ratio of IgG4/IgG (>40%) as detected using immunhistochemistry and serum IgG4 levels should be considered as a standard for the possibility of IgG4-RD. The differential diagnosis of multicentric Castleman's diseases and IgG4-RD should be also considered. Conclusions: Infiltration of plasma cells and IgG4-positive plasma cells may be detected in some types of lymphadenopathies and lymphomas in clinicopathological daily practice, but not all of them are related to IgG4-RD. It should be emphasized that the characteristics of plasma cell infiltration and the ratio of IgG4/IgG (>40%) should be considered for further differential diagnosis and avoiding misclassification of lymphadenopathies.
目的： 探讨浆细胞浸润在常见淋巴结病变中的诊断与鉴别诊断价值。 方法： 收集海军军医大学长海医院2012年9月至2022年8月病理档案中以淋巴结肿大为主要临床表现进行病理活检的常见淋巴结病变（不包括浆细胞肿瘤性病变）病例进行回顾性研究。通过形态学观察、免疫组织化学聚类分析浆细胞的浸润模式、克隆性、IgG及IgG4的表达特征，总结浆细胞浸润在常见淋巴结病变中的潜在诊断与鉴别诊断意义。 结果： 共收集236例常见淋巴结病变（不包括浆细胞肿瘤性病变），包括58例Castleman病，55例IgG4相关性淋巴结病，14例梅毒性淋巴结炎，2例类风湿性淋巴结炎，18例Rosai-Dorfman病，23例Kimura病，13例皮病性淋巴结炎，以及53例血管免疫母细胞性T细胞淋巴瘤，均以淋巴结肿大和伴有不同程度浆细胞浸润为特征；通过病理形态观察淋巴结结构是否破坏帮助确定良恶性；根据浆细胞分布特点进行淋巴结病的初步诊断；分析浆细胞及IgG和IgG4表达特点，并结合临床是否伴发自身免疫性疾病或全身多器官受累等排除IgG4相关性疾病（IgG4-RD）累及淋巴结，常见淋巴结病如Castleman病、Kimura病，皮病性淋巴结炎和Rosai-Dorfman病偶可伴发IgG4-RD，免疫组织化学IgG4/IgG>40%，血清IgG4水平升高应作为考虑IgG4-RD的标准，尤其需要鉴别的是多中心性Castleman病易并发IgG4-RD。 结论： 实际工作中一些淋巴结病变、部分淋巴瘤存在浆细胞浸润，并检测到IgG4阳性浆细胞，并非都与IgG4-RD有关，常规分析浆细胞浸润特征和IgG4/IgG表达的比值（>40%），并结合临床表现对做好鉴别诊断和减少误诊至关重要。.