AJHE2504 - CME/CMLE - How I Diagnose High-Grade B-cell Lymphoma-How I Diagnose High-Grade B-cell Lymphoma

How I Diagnose High-Grade B-cell Lymphoma

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The article focuses on High-grade B-cell lymphomas (HGBLs), which encompass a range of lymphomas characterized by overlapping morphologic and immunophenotypic features, yet they possess divergent genetic traits. It emphasizes that accurate diagnosis and classification of HGBLs necessitate a multiparametric approach that combines clinical, morphological, immunophenotypic, and genetic findings. The article outlines differences in nomenclature and disease definitions between the WHO fifth edition (WHO-5) and the International Consensus Classification (ICC) systems, describing how these differences impact HGBL classification and reporting.<br /><br />In the diagnostic process, the review presents two cases illustrating the complexities involved in distinguishing HGBLs from other lymphomas like Burkitt lymphoma (BL) and B-lymphoblastic leukemia/lymphoma (B-LBL/ALL), especially noting the importance of morphological and genetic distinctions. The role of genetic rearrangements involving MYC, BCL2, and BCL6, often referred to as "double hit" or "triple hit" cases, is highlighted as crucial in differentiation. It also discusses molecular and genetic features specific to different subtypes within HGBLs and the challenges posed by such complexity.<br /><br />Further, the article explores the significance of TdT expression in distinguishing between B-LBL/ALL and HGBLs, noting that TdT's presence does not clearly segregate these lymphomas into separate categories, necessitating a comprehensive approach for proper classification. It outlines a recommended pathologic workup that includes immunohistochemistry panel and FISH studies to confirm diagnoses, key for guiding appropriate treatment strategies.<br /><br />Ultimately, the authors stress the necessity for an integrated diagnostic approach to ensuring precise categorization of these lymphomas, which is essential for ensuring appropriate treatment is administered, given their aggressive nature and variable prognosis across subtypes. The review serves as a detailed exploration of current diagnostic challenges and methodologies in managing high-grade B-cell lymphomas.

Keywords

High-grade B-cell lymphomas

HGBLs

diagnosis

classification

morphologic features

genetic traits

MYC rearrangements

immunophenotypic features

TdT expression

pathologic workup