Diffuse large B-cell lymphomas (DLBCLs) and Burkitt lymphoma (BL) account for the majority of aggressive lymphomas in adults and children. DLBCLs exhibit marked biological heterogeneity and variable clinical presentation and clinical course. Conversely, BL is genetically relatively homogeneous but associated with variable clinicopathological features. In this article, the authors summarize the recent advances pertaining to these B-cell neoplasms, following the latest World Health Organization classification and focusing on changes introduced since the previous edition. These changes include the addition of variants and subgroups of DLBCLs and "borderline" categories for high-grade B-cell neoplasms that show features intermediate between DLBCL and classical Hodgkin lymphoma, or between DLBCL and BL. In particular, the diagnostic and therapeutic problems related to neoplasms with features intermediate between DLBCL and BL will be discussed.