New classifications of malignant lymphomas - What changes are relevant for practice?

Abstract

An internationally uniform lymphoma classification is of fundamental importance for the comparability of clinical studies. There are currently 2 parallel classifications: the "International Consensus Classification" and the WHO-classification. Follicular lymphoma 3B is classified separately as follicular large cell lymphoma in WHO-HAEM5. The diagnostic criteria of lymphoplasmocytic lymphoma (LPL) have been adjusted, both classifications recommend molecular testing for MYD88 and CXCR4 mutations. There are no significant diagnostic changes in aggressive B-cell lymphomas. The ICC classify NLPBL and THRLBCL into the group of large B-cell lymphomas (LBCL). NLPHL/NLPBL-specific therapy must be considered, which differs greatly from the therapy of DLBCL, especially in the early stages. Peripheral T-cell lymphomas are a group of nodal T-cell lymphomas with a TFH phenotype and frequent mutations; peripheral T-cell lymphoma (NOS) is therefore a diagnosis of exclusion. Indolent T-cell lymphomas/lymphoproliferations of the GI tract are rare but must be differentiated from aggressive T-cell lymphomas. The WHO-HAEM5 also includes reactive/non-neoplastic lymph node lesions classified according to B or T cell predominance.