Diffuse Large B-cell Lymphoma--more Than a Diffuse Collection of Large B Cells: an Entity in Search of a Meaningful Classification

Context: Diffuse large B-cell lymphoma is a heterogeneous group of lymphomas. In this review, we present a brief description of the large number of entities recognized in the recently published (2008) World Health Organization classification of tumors of hematopoietic and lymphoid tissues.

Objective: We highlight the unique clinicopathologic and molecular genetic features of these new and previously recognized entities, to illustrate the rational for the development of this classification. To help simplify the understanding of this now large and complex group of diseases, we have attempted to create broader subgroups of related entities. We discuss large B-cell lymphoma that are not otherwise specified, those that are based on anatomic site, those that have unique histology or phenotype or genotype, those that are associated with Epstein-Barr virus or Kaposi sarcoma-associated herpesvirus and herpesvirus 8, and those that are unclassifiable.

Data Sources: World Health Organization classification of tumors of hematopoietic and lymphoid tissues (2008), published literature from PubMed (National Library of Medicine), and primary material from the authors' institution were reviewed.

Conclusions: Recognition of the different subtypes of diffuse large B-cell lymphoma as described in the World Health Organization classification scheme will lead to improved understanding of the unique clinicopathologic and genetic features associated with these subtypes of lymphoma.