Pathology of peripheral T-cell lymphomas: where do we stand?
Peripheral T-cell lymphomas (PTCLs) are heterogeneous and uncommon malignancies characterized by a usually aggressive clinical course. The current World Health Organization (WHO) classification delineates many entities grouped according to the clinical presentation as predominantly leukemic, cutaneous, extranodal, or nodal diseases. Yet, few genetic lesions serve as entity-defining markers. Using high-throughput methods, new recurrent genetic and molecular alterations are being discovered that are expected to refine the current classification and serve as diagnostic genetic markers and targets for novel therapies. There is increasing evidence that certain cellular subsets, in particular follicular helper T cells and gamma delta T cells, represent important defining markers and/or determinants of the biology of certain entities; nevertheless, the cellular derivation of many PTCL entities remains poorly characterized and there is evidence of plasticity in terms of cellular derivation (alpha-beta, gamma-delta, natural killer [NK]) especially in several extranodal entities with a cytotoxic profile. While most clonal NK/T-cell proliferations are in general highly malignant, some more indolent forms of NK or T-cell lympho-proliferations are being identified.
Department of Pathology, AP-HP, Groupe hospitalier Henri Mondor-Albert Chenevier, Créteil, France; Université Paris-Est, Faculté de Médecine, Créteil, France; Inserm U955, Institut Mondor de Recherche Biomédicale, Créteil, France. Electronic address: philippe.gaulard@hmn.aphp.fr.
Philippe
P
Gaulard
Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Laurence
L
de Leval
D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology; D016411:Lymphoma, T-Cell, Peripheral / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D009389:Neovascularization, Pathologic; D010641:Phenotype; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology
D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases