血管免疫母细胞性T细胞淋巴瘤侵犯骨髓相关病理特征分析

Pathological characteristics of angioimmunoblastic T cell lymphoma with bone marrow involvement

目的探讨血管免疫母细胞性T细胞淋巴瘤(angioimmunoblastic T cell lymphoma,AITL)侵犯骨髓的病理特征。方法回顾性分析32例AITL侵犯骨髓的临床病理特征,采用免疫组化EnVision法和流式细胞术检测AITL相关免疫标记,通过T系基因重排分析T细胞克隆性。结果肿瘤细胞浸润模式主要以结节状(20/32,62.5%)、间质性或小簇状(10/32,31.3%)为主,结节成分较杂,可呈“肉芽肿样改变”;肿瘤细胞主要为小至中等大小淋巴细胞,异型不明显,少数病例可出现明显浆细胞增生。19例行免疫组化染色,CD4阳性T细胞较少,平均为8.4%;滤泡辅助T细胞(T follicular helper cells,TFH)相关免疫组化标记阳性率分别为:CD10(7/14,50.0%)、BCL6(6/19,31.6%)、PD-1(13/19,68.4%)、CXCL13(13/19,68.4%),大部分病例肿瘤细胞PD-1和CXCL13同时阳性,且阳性细胞数量较少(均<1%)。24例行流式细胞术检测,其中22例均一致性表达胞质CD3(cCD3)、CD5、CD4、CD2,均不同程度表达CD10,部分病例胞膜CD3(sCD3)表达缺失(12/22,54.5%),部分病例CD7表达缺失(8/22,36.4%);2例未发现异常T细胞。基因重排:7例行T系基因重排检测,其中3例TCR重排阳性。结论AITL侵犯骨髓的肿瘤细胞比例较低且异型性小,容易漏诊及误诊,当骨髓中出现细胞成分较杂的淋巴细胞灶,提示AITL侵犯骨髓。流式细胞术发现表型异常T细胞(CD4和CD10双阳性),强烈提示AITL侵犯骨髓。AITL侵犯骨髓的诊断应综合考虑骨髓活检、流式细胞术及基因重排等检查结果。

Purpose To explore the pathological features of angioimmunoblastic T-cell lymphoma(AITL)with bone marrow involvement and to improve awareness of bone marrow infiltration in AITL.Methods The tissue morphology of 32 cases of AITL with bone marrow involvement was retrospectively analyzed.Immunohistochemistry using the EnVision method and ten-color flow cytometry were conducted to detect AITL-related immune markers.T cell clonality was analyzed through T cell receptor(TCR)gene rearrangement.Results The predominant patterns of tumor cell infiltration were nodular(20/32,62.5%)and interstitial or small clusters(10/32,31.3%).The nodules showed a mixture of cellular components.In some cases,the foci contained a mixture of cells with characteristic“granulomatoid”changes.The tumor cells were mainly small to medium-sized lymphocytes with inconspicuous atypia.Some cases showed plasma cell proliferation.19 cases were subject to immunohistochemical staining,which revealed a low count of CD4-positive T cells,with an average of 8.4%.The positive rates of T follicular helper cells(TFH)markers were as follows:CD10(7/14,50.0%),BCL6(6/19,31.6%),PD-1(13/19,68.4%),and CXCL13(13/19,68.4%).In most cases,tumor cells showed co-expression of PD-1 and CXCL13,but the number of positive cells was less than 1%.Flow cytometry analysis was performed in 24 cases,among which 22 cases all consistently expressed cytoplasmic CD3(cCD3),CD5,CD4,and CD2,with varying degrees of CD10 expression.In some cases,there was a lack of expression of surface CD3(sCD3)(12/22,54.5%),while there was a lack of expression of CD7(8/22,36.4%).and no abnormal T cells were found in 2 cases.TCR gene rearrangement analysis was performed in 7 cases,with 3 cases showing TCR clonality.Conclusion AITL with bone marrow involvement exhibits a lower proportion of tumor cells and less atypia,making it prone to misdiagnosis.The presence of lymphocytic foci with mixed cellular components in the bone marrow can indicate bone marrow involvement in AITL.Flow cytometry detection of abnormal T cells(double positive for CD4 and CD10)strongly suggests bone marrow infiltration in AITL.A comprehensive diagnosis of bone marrow involvement in AITL requires consideration of bone marrow biopsy,flow cytometry,and TCR gene rearrangement analysis.