T-Cell Lymphomas in South America and Europe

Abstract

Peripheral T-cell lymphomas are a group of rare neoplasms originating from clonal proliferation of mature post-thymic lymphocytes with different entities having specific biological characteristics and clinical features. As natural killer cells are closely related to T-cells, natural killer-cell lymphomas are also part of the group. The current World Health Organization classification recognizes four categories of T/natural killer-cell lymphomas with respect to their presentation: disseminated (leukemic), nodal, extranodal and cutaneous. Geographic variations in the distribution of these diseases are well documented: nodal subtypes are more frequent in Europe and North America, while extranodal forms, including natural killer-cell lymphomas, occur almost exclusively in Asia and South America. On the whole, T-cell lymphomas are more common in Asia than in western countries, usually affect adults, with a higher tendency in men, and, excluding a few subtypes, usually have an aggressive course and poor prognosis. Apart from anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, that have a good outcome, other nodal and extranodal forms have a 5-year overall survival of about 30%. According to the principal prognostic indexes, the majority of patients are allocated to the unfavorable subset. In the past, the rarity of these diseases prevented progress in the understanding of their biology and improvements in the efficaciousness of therapy. Recently, international projects devoted to these diseases created networks promoting investigations on T-cell lymphomas. These projects are the basis of forthcoming cooperative, large scale trials to detail biologic characteristics of each sub-entity and to possibly individuate targets for new therapies.

Oral and cutaneous lymphomas other than mycosis fungoides and sézary syndrome in a mexican cohort: Recategorization and evaluation of international geographical disparities

“…The former was led by CD30+ lymphoprolifeative disorders, in accordance with other international reports,[2829303132333435363738394041] followed closely by EBV-related NK/T-cell malignancies (PC-NK/TCL and HVLLPD), commonly reported in Asia and Central America but exceptionally in Europe and the USA. [3132333435363738394041434445464748] This comparatively higher frequency could potentially be explained by previously described higher prevalence of EBV subtypes associated to human pathology in developing countries and plausibly to the onset of infection at an earlier age. [49] The same argument could hold true, to the existence of one case of EBV+ DLBCL NOS among our small cohort of 7 PC-BCL, reportedly one of the rarest entities among all PCL.…”

“…[30] While only one-third of the non-MF/SS PCL in our laboratory could be properly reclassified due to limited tissue availability, the frequency of lymphoma variants seems to differ in some aspects from both European/USA and South American registries. [282930313233343536373839404142] As in other international cohorts, non-MF/SS PC-TCL outnumbered PC-BCL. The former was led by CD30+ lymphoprolifeative disorders, in accordance with other international reports,[2829303132333435363738394041] followed closely by EBV-related NK/T-cell malignancies (PC-NK/TCL and HVLLPD), commonly reported in Asia and Central America but exceptionally in Europe and the USA.…”

“…Surprisingly, no cases of PC-MZL were observed despite being reported as the second most common form of PC-BCL in European, USA, and South American studies, and speculated to be closely linked in its pathogenesis to microbial and/or autoimmune antigenic triggers, with potential geographical restrictions. [8282930313233343536373839404142434445464748] This apparent null incidence in our cohort could be artificial; however, since PC-MZL was recently described, and formerly reported in our institution as B-cell predominant cutaneous pseudolymphoma (cutaneous lymphoid hyperplasia) before ISH for immunoglobulin light chains became available. Similarly, our cohort lacks cases of PC CD4+ small/medium T-cell lymphoproliferative disorder which until recently would have likely been diagnosed in our institution as pseudolymphomatous folliculitis but is thought to represent one of the most common non-MF/SS PCL in some recent series.…”

“…[282930313233343536373839404142] As in other international cohorts, non-MF/SS PC-TCL outnumbered PC-BCL. The former was led by CD30+ lymphoprolifeative disorders, in accordance with other international reports,[2829303132333435363738394041] followed closely by EBV-related NK/T-cell malignancies (PC-NK/TCL and HVLLPD), commonly reported in Asia and Central America but exceptionally in Europe and the USA. [3132333435363738394041434445464748] This comparatively higher frequency could potentially be explained by previously described higher prevalence of EBV subtypes associated to human pathology in developing countries and plausibly to the onset of infection at an earlier age.…”

The Value and Relevance of the T Cell Lymphoma Registries and International Collaborations: the Case of COMPLETE and the T-Cell Project

“…Results of diverse preliminary analyses have been reported for both COMPLETE [18,[33][34][35][36][37] and the T-Cell Project [30][31][32][38][39][40][41][42]. The production originated so far from the two registries is summarized in Table 2.…”