Large B-Cell Lymphomas of the Spleen

Abstract

The diagnosis of diffuse large B-cell lymphoma (DLBCL) in the current era is complex and involves a subclassification scheme that incorporates morphologic, immunophenotypic, and genetic features. In addition, there are large B-cell lymphomas that have a unique biology or site predilection, which justifies the use of separate diagnostic terminologies (e.g., Epstein-Barr virus (EBV)+ DLBCL, not otherwise specified (NOS); primary DLBCL of the CNS; primary cutaneous DLBCL, leg type; DLBCL associated with chronic inflammation; plasmablastic lymphoma etc. ). This chapter covers large B-cell lymphomas that are known to involve the spleen, primary or secondary. The most common lymphoma of the spleen is DLBCL, NOS, and most of these are secondary in nature. We discuss both the common macronodular manifestation and the less common diffuse red pulp variant of DLBCLs. T-cell-/histiocyte-rich large B-cell lymphoma (TCRBL) has morphologic features (micronodular) unique to the spleen as compared to the typical morphology observed in nodal TCRBL. EBV+ DLBCL, NOS, of the spleen has morphology similar to that observed in other sites, however, with important differential diagnoses that need to be considered. Lastly, we discuss the recently introduced high-grade B-cell lymphomas (HGBL), which include double-/triple-hit lymphomas (involving MYC, BCL2, and/or BCL6 translocations) and high-grade B-cell lymphoma, NOS.