Updated knowledge about lymphoma pathology has been accumulated ever since the publication of the current WHO classification of lymphomas in 2008. For B-cell non-Hodgkin lymphomas

endeavors have been made for approaching a better classification of those highly aggressive and heterogeneous subtypes (e.g.

diffuse large B-cell lymphomas) on the molecular biological basis. In addition

there is a growing interest in understanding and dealing with the borders of overt malignant lymphomas and certain clonal lymphproliferative disorders that are not overtly malignant. On the other hand

recent advances in understanding the subsets of T and NK (T/NK)-cell lineage and their differentiation

as well as the genetic aberrations or dysregulated signaling pathways in their neoplastic counterparts

have provided us novel insights into the biology of peripheral T/NK-cell lymphomas. Indolent clonal T/NK-cell proliferations

especially those arising from the mucocutaneous sites

have also received increased attention. These advances may contribute to the evolution of the classification of lymphomas.