Department of Diagnostic Pathology, Osaka Red Cross Hospital, Osaka, Japan.
Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
J Clin Exp Hematop. 2024;64(3):203-207. doi: 10.3960/jslrt.24025.
Primary diffuse large B-cell lymphoma of the central nervous system (CNS-DLBCL) can be difficult to diagnose because of the limited amount of biopsy tissue. Here, we analyzed the utility of insulin-like growth factor II mRNA binding protein 3 (IMP3) immunohistochemistry (IHC) as an adjunctive diagnostic tool for CNS-DLBCL. IHC was performed on 57 biopsy samples (55 brain biopsy samples and two vitreous cell blocks) from 54 patients with CNS-DLBCL, including three biopsy samples initially diagnosed as negative or indeterminate for CNS-DLBCL. Additionally, IMP3 IHC was performed on 68 DLBCLs other than CNS-DLBCL and 12 inflammatory brain diseases. Cytoplasmic IMP3 expression was noted in ≥50% of tumor cells in 100% (57/57) of CNS-DLBCLs and 88.2% (60/68) of non-CNS-DLBCLs. In contrast, no IMP3-positive CD20-positive B cells were observed in the inflammatory brain disease (P < 0.0001). In conclusion, IMP3 is highly expressed in CNS-DLBCL. However, it is also expressed in other types of DLBCLs, making it less specific. Most CNS-DLBCL cases can be diagnosed without performing IHC for IMP3 expression, but it may be a useful adjunctive tool to differentiate from reactive lesions when tumor cells are few or deformed.
原发性中枢神经系统弥漫性大 B 细胞淋巴瘤（CNS-DLBCL）由于活检组织量有限，诊断较为困难。在这里，我们分析了胰岛素样生长因子 II mRNA 结合蛋白 3（IMP3）免疫组化（IHC）作为 CNS-DLBCL 辅助诊断工具的效用。对 54 例 CNS-DLBCL 患者的 57 个活检样本（55 个脑活检样本和 2 个玻璃体细胞块）进行了 IHC 检测，包括 3 个最初诊断为 CNS-DLBCL 阴性或不确定的活检样本。此外，对 68 例非 CNS-DLBCL 和 12 例炎症性脑疾病进行了 IMP3 IHC 检测。在 100%（57/57）的 CNS-DLBCL 和 88.2%（60/68）的非 CNS-DLBCL 中，肿瘤细胞的细胞质 IMP3 表达≥50%。相比之下，在炎症性脑疾病中未观察到 IMP3 阳性 CD20 阳性 B 细胞（P < 0.0001）。总之，IMP3 在 CNS-DLBCL 中高度表达。然而，它也在其他类型的 DLBCL 中表达，因此特异性较低。大多数 CNS-DLBCL 病例无需进行 IMP3 表达的 IHC 即可诊断，但当肿瘤细胞较少或变形时，它可能是一种有用的辅助工具，可用于与反应性病变进行鉴别。
