From Biopsy to Diagnosis: Navigating Aggressive B-Cell Lymphomas in Practice.

Diffuse large B-cell lymphoma (DLBCL), recognized as the most prevalent variant of adult non-Hodgkin lymphoma, presents considerable challenges in diagnosis owing to its diverse morphological features and frequent extranodal involvement, which may frequently mimic nonhematopoietic neoplasms. The 2022 WHO Classification of Lymphoid and Hematopoietic Tissues provides essential updates, highlighting the necessity of combining morphology, immunohistochemistry, cytogenetics, and molecular testing for precise subclassification. This review presents a practical method for differentiating DLBCL from other aggressive B-cell neoplasms, such as Burkitt lymphoma, B-lymphoblastic lymphoma, and mantle cell lymphoma. It highlights vital diagnostic tools, including CD45, B/T-cell markers, germinal center markers, and the Hans algorithm, as well as the role of FISH in identifying rearrangements of key genes MYC, BCL2, and BCL6, which are significant for recognizing double-hit and triple-hit lymphomas. Special focus is given to EBV-associated DLBCL and uncommon subtypes featuring plasmablastic or ALK-positive traits. This review aims to enhance diagnostic accuracy and ensure appropriate treatment strategies for patients with large B-cell lymphomas by emphasizing thorough morphological evaluation, specific adjunct testing, and adherence to the most recent classification standards.