Department of Oncology and Hematology, Shimane University Hospital, Izumo, Japan.
Department of Pathology, Kurume University School of Medicine, Kurume, Japan.
Am J Clin Pathol. 2021 Feb 4;155(2):308-317. doi: 10.1093/ajcp/aqaa126.
We report a rare case of B-lymphoblastic lymphoma (B-LBL) and low-grade follicular lymphoma (FL) identified concurrently in biopsies from different sites at the initial diagnosis in a 39-year-old man. The clonal relationship between the 2 histologic subtypes was investigated.
A diagnosis of FL grade 1/2 (low grade) was made by bone marrow (BM) biopsy. B-LBL was identified in biopsies from the testis and pancreas. Cytogenetic and molecular analyses were performed to investigate their clonal relationship.
Interphase fluorescence in situ hybridization analyses and G-banding karyotype analyses identified the BCL2-IGH and MYC-IGH translocation in tumor cells from both the BM and testis. The tumor cells from the BM and testis shared the same IGH VDJ usage and a high degree of somatic mutations. These findings suggest that acquisition of MYC gene rearrangement is a critical event for lymphoblastic transformation of FL. Of note, the presence of intraclonal diversity in the B-LBL sample further suggests an earlier or concurrent event of MYC translocation than the somatic IGH mutation in the germinal center and the dedifferentiation of lymphoma cells to a precursor stage of B-cell development.
B-lymphoblastic transformation of FL can occur with MYC gene rearrangement.
我们报告了一例罕见的病例，一名 39 岁男性在初始诊断时，不同部位的活检同时发现 B 淋巴细胞性淋巴瘤（B-LBL）和低级别滤泡性淋巴瘤（FL）。我们研究了这两种组织学亚型之间的克隆关系。
骨髓活检诊断为 FL 1/2 级（低级别）。在睾丸和胰腺活检中发现 B-LBL。进行细胞遗传学和分子分析以研究其克隆关系。
间期荧光原位杂交分析和 G 带核型分析确定了来自 BM 和睾丸的肿瘤细胞中的 BCL2-IGH 和 MYC-IGH 易位。来自 BM 和睾丸的肿瘤细胞共享相同的 IGH VDJ 使用和高度体细胞突变。这些发现表明，MYC 基因重排的获得是 FL 淋巴细胞性转化的关键事件。值得注意的是，B-LBL 样本中存在克隆内多样性进一步表明，MYC 易位发生在生发中心体细胞 IGH 突变之前或同时，并且淋巴瘤细胞向 B 细胞发育的前体细胞阶段去分化。
FL 可发生伴有 MYC 基因重排的 B 淋巴细胞性转化。
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