Fig. 1.

Cell-of-origin and classification of mature B-cell neoplasms

The different lymphoma subtypes are classified based on their histological architecture, cellular morphology, immunophenotype, genetic characteristics, and correspondence to the normal stages of B-cell development, such as naïve, germinal center, and post germinal center cells. Follicular lymphoma comprises germinal center B-cells similar to those found in secondary lymphoid follicles. It is composed of a mixture of small (centrocytes) and larger neoplastic cells (centroblasts) that have the t(14;18)/IGH::BCL2 fusion gene.