Clinical manifestation and treatment of extranodal diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) accounts for 30-40% of all lymphoma subtypes. More than half of DLBCLs are estimated to arise from extranodal sites, and are called extranodal DLBCLs. Generally, the outcomes of extranodal DLBCL are not different from those of nodal DLBCL. To our knowledge, this report is the first to discuss the concept and the cell of origin of extranodal DLBCL, with the significance of the presence/absence of each involvement site in determining the outcome. Second, the evidence of clinical manifestation and outcomes of several extranodal DLBCLs requiring treatments other than R-CHOP, which is the current standard therapy for this malignancy, are discussed. Most primary central nervous system (CNS) and testicular lymphomas are histologically DLBCLs. Moreover, primary mediastinal and intravascular large B-cell lymphomas are subtypes of DLBCL by definition. Hence, the evidence of high-risk sites for CNS involvement is also described.