第二十一届欧洲血液病理学协会和血液病病理学协会联合会议的淋巴瘤研讨会第三个专题在2022年9月22日于意大利佛罗伦萨举行。此次研讨会的专题内容包括脾脏和淋巴结边缘区淋巴瘤、边缘区淋巴瘤的转化，以及儿童淋巴结边缘区淋巴瘤及相关疾病的鉴别诊断。共提交了42例符合以上分类的病例，其中包括脾淋巴瘤（边缘区淋巴瘤和弥漫性红髓淋巴瘤），转化的边缘区淋巴瘤（脾和淋巴结），伴有TFH细胞增多的淋巴结边缘区淋巴瘤，以及儿童淋巴结边缘区淋巴瘤。案例回顾突出了边缘区淋巴瘤诊断中的一些主要问题，比如脾脏边缘区淋巴瘤、脾弥漫性红髓淋巴瘤和毛细胞白血病变异型/突出核仁的脾B细胞淋巴瘤之间的区别困难，需要综合考虑临床特征、免疫表型和血液、骨髓和脾脏的形态学；边缘区淋巴瘤伴有明显增多的TFH细胞，模拟T细胞淋巴瘤，在终诊时分子研究（克隆性和突变检测）可以帮助明确诊断；边缘区淋巴瘤转化的标准仍不清楚，可能需要结合形态学和分子数据；儿童淋巴结边缘区淋巴瘤和儿童型滤泡淋巴瘤之间存在重叠光谱的概念；以及儿童淋巴结边缘区淋巴瘤与“非典型”边缘区增生之间的区别，需要进行分子研究以正确分类案例。©2023. 作者.

Session 3 of the lymphoma workshop of the XXI joint meeting of the European Association for Haematopathology and the Society for Hematopathology took place in Florence, Italy, on September 22, 2022. The topics of this session were splenic and nodal marginal zone lymphomas, transformation in marginal zone lymphomas, and pediatric nodal marginal zone lymphomas and their differential diagnosis as well as related entities. Forty-two cases in these categories were submitted to the workshop, including splenic lymphomas (marginal zone and diffuse red pulp lymphomas), transformed marginal zone lymphomas (splenic and nodal), nodal marginal zone lymphomas with increased TFH-cells, and pediatric nodal marginal zone lymphomas. The case review highlighted some of the principal problems in the diagnosis of marginal zone lymphomas, including the difficulties in the distinction between splenic marginal zone lymphoma, splenic diffuse red pulp lymphoma, and hairy cell leukemia variant/splenic B-cell lymphoma with prominent nucleoli which requires integration of clinical features, immunophenotype, and morphology in blood, bone marrow, and spleen; cases of marginal zone lymphoma with markedly increased TFH-cells, simulating a T-cell lymphoma, where molecular studies (clonality and mutation detection) can help to establish the final diagnosis; the criteria for transformation of marginal zone lymphomas, which are still unclear and might require the integration of morphological and molecular data; the concept of an overlapping spectrum between pediatric nodal marginal zone lymphoma and pediatric-type follicular lymphoma; and the distinction between pediatric nodal marginal zone lymphoma and "atypical" marginal zone hyperplasia, where molecular studies are mandatory to correctly classify cases.© 2023. The Author(s).