滤泡变型外周T细胞淋巴瘤临床病理学及遗传学分析

Follicular variant of peripheral T-cell lymphoma： a clinicopathologic and genetic study of 2 cases

目的 观察滤泡变型外周T细胞淋巴瘤的临床病理特征和遗传学改变,探讨其与血管免疫母细胞性T细胞淋巴瘤的关系.方法 对2例滤泡变型外周T细胞淋巴瘤进行临床资料分析和组织病理学观察,以免疫组织化学染色（除CXCL13为三步SP法外,其余均为EnVision法）和EBER原位杂交方法分析肿瘤免疫表型和EB病毒感染状况,并分别以聚合酶链反应（PCR）和逆转录聚合酶链反应（RT-PCR）方法检测IgH、T细胞受体（TCR）基因克隆性重排和ITK/SYK融合基因转录本表达情况.结果 2例患者均以浅表淋巴结肿大为主要表现.镜下观察,例1示紧密排列的滤泡/结节状淋巴组织增生,结节内无明显生发中心,肿瘤细胞以中、小透亮细胞为主.例2左颈病变也主要表现为滤泡/结节状淋巴组织增生,但右颈病变大部分区域呈现典型血管免疫母细胞性T细胞淋巴瘤组织学图像.2例肿瘤细胞均表达滤泡辅助T细胞标记（CD3、CD4、CD10、PD1及CXCL13阳性）.例1的EBER原位杂交阴性.例2有散在EBER阳性的反应性转化B细胞存在.分子遗传学检测示2例均有TCR基因单克隆性重排而无ITK/SYK融合基因表达.结论滤泡变型外周T细胞淋巴瘤作为一种少见的外周T细胞淋巴瘤的形态学变型,不但免疫表型和血管免疫母细胞性T细胞淋巴瘤相似,其组织学形态也与后者有着相似或重叠之处,提示两者密切相关或存在互相演进关系.

Objective To observe the clinicopathologic and genetic features of follicular variant of peripheral T-cell lymphoma （FV-PTCL）, with particular attention to the relationship of this type of lymphoma with angioimmunoblastic T-cell lymphoma （AIIL）. Methods The clinical data, hemstoxylin and eosin-stained sections of lymph node biopsies from 2 FV-PTCL cases were reviewed.Immunohistochemical phenotyping and detection of EBV-encoded RNAs （EBER） through in situ hybridization （ISH） were performed. The EnVision two-step method was used for all antibodies except CXCL13 （by using three-step streptavidin immunoperoxidase method）. Analysis of clonality and ITK/SYK gene rearrangement was conducted using PCR and RT-PCR assays, respectively. Results Clinically, the two patients presented with superficial lymphadenopathy similarly. Histologically, case 1 showed a follicular/nodular lymphoid proliferation without marked germinal centers. The neoplastic cells comprised mainly medium sized cells with abundant, sometimes clear cytoplasms. Similar histologic findings were seen in case 2 in addition to a concurrent component mimicking typical AITL noticed. Of both cases, the neoplastic cells showed positive reactivity to CD3, CD4, CD10, PD1, and CXCL13. Positive hybridization signals for EBER were only seen in case 2, and double stains demonstrated that those EBV-positive cells were mostly the reactive transformed B-cells. Monoclonal T-cell proliferation was proved by the rearranged TCR gene detection in both cases. Neither of the current cases expressed ITK/SYK fusion transcripts. Conclusion FV-PTCL shows the similar or overlapped morphological and immunophenotypic features to those of AITL,possibly suggesting the presence of a potential relationship between these two types of lymphomas.