Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common variant of non-Hodgkin's lymphoma and accounts for about 1/3 of all non-Hodgkin's lymphomas in Western countries and about 40% of B-cell tumors worldwide. Correct diagnosis of clinically distinct subgroups of aggressive mature B-cell lymphomas is crucial for the choice of adequate treatment. Currently, the identification of DLBCL subtype depends on a combination of morphologic, immunophenotypic, and cytogenetic/molecular features. The classification covers the most common unspecified variant of DLBCL, also referred to as "not otherwise specified" (NOS), and a number of other rare forms. Over the past two decades, DLBCL NOS which accounts for more than 80% of all cases, has been the subject of a growing number of molecular studies that have identified prognostic factors that are being actively introduced into real-world clinical practice. Only the integration of morphological, immunohistochemical and molecular features of DLBCL will lead to the achievement of the long-term goal of curing the majority of patients with minimal or no toxic manifestations with the aid of personalized healthcare.