A practical approach to the modern diagnosis and classification of T-and NK-cell lymphomas.

in Blood by Laurence L de Leval, Philippe Gaulard, Ahmet Dogan

TLDR

  • T- and NK-cell lymphomas are a type of cancer that starts in the immune system. These cancers can be difficult to diagnose because they can look like other types of cancer or benign growths. The study provides a comprehensive overview of how to diagnose T-cell lymphoma and highlights the challenges in doing so. The study also suggests that future research could help improve the accuracy of diagnosis and explore the role of the immune system in these cancers.

Abstract

T- and NK-cell lymphomas are neoplasms derived from immature T cells (lymphoblastic lymphomas), or more commonly, from mature T and NK cells (peripheral T-cell lymphomas, PTCLs). PTCLs are rare but show marked biologic and clinical diversity. They are usually aggressive and may present in lymph nodes, blood, bone marrow or other organs. More than 30 T/NK-cell derived neoplastic entities are recognized in the International Consensus Classification and the classification of the World Health Organization (5th edition), both published in 2022, which integrate most recent knowledge in hematology, immunology, pathology and genetics. In both proposals, disease definition aims to integrate clinical features, etiology, implied cell of origin, morphology, phenotype and genetic features into biologically and clinically relevant clinico-pathologic entities. Cell derivation from innate immune cells, or specific functional subsets of CD4+ T cells like follicular helper T cells, are major determinants delineating entities. Accurate diagnosis of T/NK-cell lymphoma is essential for clinical management and mostly relies on tissue biopsies. Because the histologic presentation may be heterogeneous and overlaps with that of many benign lymphoid proliferations and B-cell lymphomas, the diagnosis is often challenging. Disease location, morphology and immunophenotyping remain the main features guiding the diagnosis, often complemented by genetic analysis including clonality and high-throughput sequencing mutational studies. This review provides a comprehensive overview of the classification and diagnosis of T-cell lymphoma in the context of current concepts and scientific knowledge.

Overview

  • The study focuses on T- and NK-cell lymphomas, which are derived from immature T cells or mature T and NK cells. These neoplasms are rare but show marked diversity in biology and clinical presentation. The study aims to provide a comprehensive overview of the classification and diagnosis of T-cell lymphoma in the context of current concepts and scientific knowledge.

Comparative Analysis & Findings

  • The study compares the outcomes observed under different experimental conditions or interventions, such as tissue biopsies and genetic analysis. The results show that disease location, morphology, and immunophenotyping are the main features guiding the diagnosis of T-cell lymphoma, often complemented by genetic analysis. The study identifies the importance of accurate diagnosis for clinical management and highlights the challenges in diagnosing T-cell lymphoma due to its heterogeneous histologic presentation and overlap with benign lymphoid proliferations and B-cell lymphomas.

Implications and Future Directions

  • The study's findings highlight the importance of accurate diagnosis for clinical management and underscore the challenges in diagnosing T-cell lymphoma. Future research directions could focus on developing more sensitive and specific diagnostic tools, such as high-throughput sequencing mutational studies, to improve the accuracy of diagnosis. Additionally, further research could explore the role of innate immune cells and specific functional subsets of CD4+ T cells in the development and diagnosis of T-cell lymphoma.
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