目的 通过学习1例少见的组织学特征与IgG4相关性淋巴结病类似的浆细胞型特发性多中心型Castleman病（PC-iMCD）,总结两种易误诊疾病的鉴别要点,提高病理诊断水平。方法 回顾性分析1例PC-iMCD患者临床资料,常规苏木素-伊红（HE）染色分析淋巴结组织结构及细胞形态,免疫组织化学染色及原位杂交分析免疫表型及EB病毒（EBV）感染状态,并结合文献分析讨论其与IgG4相关淋巴结病的鉴别诊断。结果 48岁女性患者,临床表现为口干、多饮、皮肤瘙痒伴全身多处淋巴结肿大。实验室检查血清IgG、IgA、IgM及IgE水平均升高,血清IgG4显著升高（14.7 g/L）,白介素- 6（IL-6）异常升高（150.84 pg/mL）。病理检查显示淋巴结生发中心萎缩,套区淋巴细胞呈“洋葱皮”样围绕生发中心排列,滤泡间区扩张,其内见大量成熟的浆细胞呈片状浸润,灶区见含铁血黄素沉积及血管增生;免疫组化染色显示IgG4阳性浆细胞数大于100/高倍视野,IgG4阳性细胞/IgG阳性细胞比值>40%,Kappa及Lambda轻链呈非限制性表达;EB病毒编码RNA原位杂交（EBER）阴性。结论 部分PC-iMCD与IgG4相关淋巴结病具有相似的组织病理学特征,单纯根据组织学及免疫表型难以将两者鉴别,正确诊断需结合IgG4相关病变诊断标准、排除性诊断标准、临床表现及实验室检查综合判断。

Objective By studying a rare case of the plasma cell type idiopathic multicentric Castleman disease（PC-iMCD）with histological characteristics similar to IgG4-related lymphadenopathy,the differential points of the two easily misdiagnosed diseases were summarized to improve the level of pathological diagnosis．Methods The clinical data of one patient with PC-iMCD were collected,the structure alteration and cell morphology were observed by hematoxylin-eosin（HE）stains．The immunophenotype of cells was marked by immunohistochemical staining and the infections status of EB virus was detected by in situ hybridization．Besides,the differential diagnosis between IgG4-RD and PC-iMCD were analyzed and discussed based on literature analysis．Results This article reported a 48-year-old female who was admitted to the hospital with dry mouth,polydipsia,skin itching and multiple lymphadenopathy．The levels of various classes of serum immunoglobulin were all increased,such as IgG,IgA,IgM and IgE．Specially,the serum IgG4 was also significantly increased（14.7 g/L）and interleukin 6（IL-6）was abnormally raised（150.84 pg/mL）．The pathological examination indicated that the lymph node germinal center was atrophied and mantle zones were expanded which were composed of concentric rings of lymphocytes in an “onion skinning” appearance．Besides,the interfollicular area was expanded in which mature plasma cells were infiltrated in sheet-like,hemosiderin was deposited as well as the vessels were proliferated．Immunohistochemistry showed that the number of IgG4-positive plasma cells was >100/HPF,IgG4/IgG-positive cells ratio was >40%,and Kappa and Lambda light chains were expressed unrestrictedly．In situ hybridization revealed that the expression of EBER was negative．Conclusions PC-iMCD and IgG4-related lymphadenopathy shares similar histopathological characteristics and it’s challenging to distinguish these two diseases by their histology and immunophenotype．In conclusion,the correct diagnosis should be combined with the diagnostic criteria,exclusion diagnostic criteria,clinical manifestations and related laboratory examinations．

目的 学习母细胞性浆细胞样树突细胞肿瘤(BPDCN)的临床病理及免疫表型特征,总结该少见肿瘤的病理诊断经验。方法 回顾分析2例BPDCN患者临床资料,通过苏木素-伊红(HE)染色分析肿瘤组织及细胞形态,通过免疫组织化学染色分析肿瘤免疫表型,通过流式细胞学检测骨髓有无肿瘤侵犯,并结合文献分析。结果 本报道中1例为97岁女性,临床以皮肤瘀斑结节为首发症状,肿瘤细胞真皮内弥漫浸润,不侵犯表皮,细胞中等大小,核形不规则,核仁不明显。另1例为69岁男性,临床以淋巴结肿大为首发症状,淋巴结结构完全破坏,肿瘤细胞弥漫浸润,细胞呈中等大小的母细胞样,核仁明显。2例免疫表型均表达CD123、CD4、CD56、TDT,不表达B系、T系淋巴细胞及髓系标志物,肿瘤均累及骨髓。结论 BPDCN是一种罕见的淋巴造血肿瘤,临床常以皮肤病变或淋巴结肿大为首发症状,临床过程具高度侵袭性,通常伴有骨髓侵犯。该肿瘤需与具有母细胞形态的淋巴系肿瘤和白血病相鉴别,诊断需结合临床信息、HE形态及免疫组化结果综合判断。

Objective To summarize the diagnostic experiences of blastic plasmacytoid dendritic cell neoplasm (BPDCN) based on the study of its clinicopathological features and immunophenotypes. Methods The clinical data of 2 patients with BPDCN were collected, the structure alteration and cell morphology were observed by HE staining, the immunophenotype of tumor cells were studied by immunohistochemistry staining and flow cytometry was adopted to confirm the bone marrow involvement. Results Two patients, one of whom was a 97 year-old female, presented with cutaneous ecchymosis nodules as the first symptom. The epidermis, but not the dermal, was diffusedly infiltrated by tumor cells, which were medium-sized with irregular nuclei without prominent nucleoli. The other case was a 69 year-old male with lymph node enlargement as the first symptom. The skin was normal, but the lymph nodes were invasively destroyed by tumor cells, which were medium-sized blast-like with prominent nucleoli. The immunophenotypes of the two patients were both positive for CD123, CD4, CD56 and TDT, but negative for B, T lymphocyte derived and myeloid origin markers, both of which involved bone marrow. Conclusions BPDCN is a rare form of hematological neoplasm, skin symptoms or lymph node enlargement may be presented as the initial symptom, the clinical course were highly aggressive with high frequency of bone marrow involvement. The blastic-like lymphoma and leukemia entities should be considered into account for differential diagnose. The precise diagnosis of BPDCN should be established by integrating histomorphology, immunophenotype and clinical presentation information comprehensively.