Ancillary Studies in the Diagnostic Evaluation of Large B-Cell Lymphoma

Context.--Large B-cell lymphoma classification has changed significantly over the decades, evolving from a purely morphologic categorization to one using sophisticated ancillary studies including molecular analysis, immunohistochemistry, and cytogenetics, in addition to morphology and clinical presentation. Objective.--To discuss and interpret the key ancillary studies required for subclassification in 2019 and review the differential diagnosis of diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). Data Sources.--Recent literature on the subcategories of large B-cell lymphoma is reviewed, along with relevant updates from the 2016 World Health Organization Classification of Tumours of Hematopoietic and Lymphoid Tissues, with an emphasis on Epstein-Barr virus-positive lymphoproliferative disorders, high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, and large B-cell lymphoma with IRF4 rearrangement. Conclusions.--Cases with DLBCL, NOS histology can be further subclassified on the basis of cell of origin studies, Epstein-Barr virus-encoded small RNAs, MYC and BCL2 and/or BCL6 rearrangement studies, and other relevant cytogenetic and immunohistochemical studies. The diagnosis of DLBCL, NOS is therefore a diagnosis of exclusion. doi: 10.5858/arpa.2019-0331-RA
Lymphoma classification has changed significantly over the decades, evolving from a purely morphologic categorization to one using sophisticated ancillary studies including molecular analysis, immunohistochemistry, and cytogenetics, in addition to morphologic [...]