摘要目的 观察在不同类型小B细胞淋巴瘤(SBL)中滤泡树突细胞(FDC)网架的破坏情况和FDC分布特征,结合Ki-67阳性指数高低和分布方式存在的差异,探讨其在SBL鉴别诊断中的价值.方法 回顾性研究北京大学肿瘤医院2008年11月至2012年6月间诊断的68例SBL,观察CD21及CD23免疫组织化学染色显示的FDC网架破坏情况、分布形式及Ki-67阳性指数及分布形式.使用统计学软件分析其与不同SBL类型的关系.结果 68例患者年龄28 ～ 85岁,平均55.2岁；男女比1.2∶1,发病部位为淋巴结内55例(80.9％),结外13例(19.1％).复习并依据2008 WHO造血与淋巴组织肿瘤分类标准确诊病理诊断:低级别滤泡性淋巴瘤(FL,1级和2级)22例,边缘区淋巴瘤(MZL) 19例,套细胞淋巴瘤(MCL) 17例,以及慢性淋巴细胞白血病/小淋巴细胞淋巴瘤(CLL/SLL)10例.在FL中CD21及CD23标记的FDC网架是以中心破坏为主,发生比例占90.9％(20/22).而在MZL中则以FDC网架周边结构破坏为主,为14/19；在CLL/SLL则表现为散在个别FDC或者无FDC网架；对于MCL,有7/17的病例表现为散在个别FDC或者无FDC网架,另有7/17的MCL出现了FDC的不规则网状增生.FDC网架按照破坏及分布情况在不同的淋巴瘤分型中差异具有统计学意义(P＜0.01).Ki-67显示的肿瘤细胞增殖活性在4种不同SBL间差异也具有统计学意义(P＜0.05),增殖活性从高到低依次为:MCL、FL、SLL、MZL.Ki-67在FL病例可以看到滤泡中心散在表达且极向消失,MZL病例中可见残余生发中心外的肿瘤较为一致散在表达,而且两者均普遍低于残留非肿瘤性生发中心的阳性指数；在MCL中可见较为一致的分布,但个体间阳性指数差异较大(5％～90％)；在CLL/SLL病例中肿瘤的“增殖中心”Ki-67呈灶状增高.结论 通过常规使用CD21和CD23免疫组织化学染色,显示FDC网架的破坏情况,并联合Ki-67显示细胞的增殖活性,观察两者分布形式,对于明确区分各种类型的SBL具有鉴别意义.

abstractsObjective To identify the immunohistochemical patterns of follicular dendritic cell (FDC) meshwork and Ki-67 labeling index in small B-cell lymphomas (SBLs) and their significance in differential diagnosis.Methods Sixty-eight cases of SBLs were included collected from November 2008 to June 2012.The patterns of FDCs and Ki-67 expression were studied on paraffin sections by CD21,CD23 and Ki-67 immunohistochemistry.The characteristic staining patterns of FDCs and Ki-67 expression among different SBLs were analyzed statistically.Results The age of SBL patients ranged from 28 to 85 years with a mean of 55.2 years.The male to female ratio was 1.2 ∶ 1.Fifty-five cases involved only lymph nodes (80.9％),and the remaining cases involved multiple extra-nodal sites.Histological classification of the cases was made according to the 2008 WHO lymphoma classification criteria:22 were low-grade follicular lymphomas (FLs,including grade 1 and grade 2),19 marginal zone lymphomas (MZLs),17 mantle cell lymphomas (MCLs),and 10 chronic lymphocytic leukemia/small lymphocytic lymphomas (CLL/SLLs).FDC meshwork limited to the central part of neoplastic follicles was characteristic for FL(90.9％,20/22).The germinal center FDC meshwork was destroyed primarily at periphery in MZL (14/19).The absence or scattered FDC clusters were typical of SLL/ CLL.Irregular FDC was seen in 7/17 of MCL,while 7/17 MCL displayed FDC pattern similar to that of CLL/SLLs.The pattern of FDCs was a significantly diagnostic feature in distinguishing the four types of SBLs (P ＜ 0.01).Ki-67 was also a statistically significant parameter(P＜0.05) with decreasing labeling index as the following:MCL,FL,SLL and MZL.Ki-67showed scattered pattern in germinal centers with loss of polarity in FLs.MZL presented uniformly scattered positive pattern in interfollicullar areas.Ki-67 staining was uniform in MCL,but its labeling index varied from 5％ to 90％.The Ki-67 index was higher in the morphological "proliferation center" of all CLL/SLLs.Conclusion Immunohistochemieal staining patterns of FDC meshworks and Ki-67 labeling index offer a significant discriminatory power in the differential diagnoses among SBLs.