Pathology Consultation on Intermediate-to-Large B-Cell Lymphomas

Abstract

Intermediate-to-large B-cell lymphomas represent a heterogeneous group of aggressive lesions frequently encountered in practice. The differential diagnosis includes the most common of all lymphomas, diffuse large B-cell lymphoma (DLBCL), as well as Burkitt lymphoma (BL), B-lymphoblastic lymphoma, and the blastoid variant of mantle cell lymphoma. In recent decades, gene expression profiling studies have clarified the biologic origins and features of these diseases. Moreover, clinically relevant subtypes of DLBCL have been identified, and a new category was defined: B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. Herein, we review the salient diagnostic features of the various entities within this differential diagnosis and provide a stepwise diagnostic approach for dealing with challenging cases. A case-based approach is used to highlight diagnostic dilemmas and clinical decision points within the differential diagnosis of intermediate-to-large B-cell lymphomas. Based on the published literature and World Health Organization criteria, we suggest a diagnostic algorithm for appropriate classification of these lymphomas. Correct classification of intermediate-to-large B-cell lymphomas is important, because prognosis and therapeutic approach vary for different tumors and tumor subclasses. Understanding both disease-specific criteria and pathologic features that influence clinical behavior within a category is imperative for evaluation of these lymphomas.