Transdifferentiation, phenotypic infidelity, progression, and transformation in T/NK-cell neoplasms Report from the 2021 SH/EAHP workshop

Catalina Amador, James R. Cook, Magdalena Czader, Amy Duffield, John Goodlad, Reza Nejati, German Ott, Wenbin Xiao, Sandeep Dave, Mariusz A. Wasik, Ahmet Dogan

Research output: Contribution to journalReview articlepeer-review

2 Scopus citations


Objectives: Sessions 8 and 9 of the 2021 Society for Hematopathology and the European Association for Haematopathology Workshop aimed to collect examples of transdifferentiation, lineage infidelity, progression, and transformation in precursor and mature T/natural killer (NK)–cell neoplasms. Methods: Twenty-eight cases were submitted and analyzed, with whole-exome sequencing and genome-wide RNA expression analysis performed in a subset of the cases. Results: In session 8, 7 T-lymphoblastic lymphoma/leukemia cases were received that showed transdifferentiation to clonally related mature myeloid hematopoietic neoplasms, including 6 histiocytic/dendritic cell lineage neoplasms and a mast cell sarcoma. Session 9 included 21 mature T-cell neoplasms that were grouped into 3 themes. The first one addressed phenotypic infidelity in mature T-cell lymphomas (TCLs) and included 8 TCLs expressing aberrant antigens, mimicking classic Hodgkin and non-Hodgkin B-cell lymphomas. The second theme addressed disease progression in TCL and included 5 cutaneous T-cell lymphoproliferative disorders and 2 T-cell large granular lymphocyte proliferations with subsequent progression to systemic TCL. The third theme included 6 patients with TCL with T-follicular helper phenotype, mainly angioimmunoblastic T-cell lymphoma, with concurrent/subsequent clonal hematopoiesis or myeloid neoplasms and/ or subsequent/concomitant diffuse large B-cell lymphoma. Conclusions: This cohort of cases allowed us to illustrate, discuss, and review current concepts of transdifferentiation, aberrant antigen expression, and progression in various T/ NK-cell neoplasms.

Original languageEnglish
Pages (from-to)626-637
Number of pages12
JournalAmerican Journal of Clinical Pathology
Issue number6
Early online dateApr 11 2023
StatePublished - Jun 1 2023


  • Acute lymphoblastic leukemia
  • Clonal evolution
  • Clonal hematopoiesis
  • T-ALL
  • T-cell lymphoma
  • Transdifferentiation
  • Transformation


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