Approach to T-Follicular Helper (TFH) Lymphomas and Mimics

Follicular helper T-cell (TFH) lymphomas comprise a unique group of T-cell lymphomas that represent neoplastic proliferations of follicular helper T-cells and share genetic, immunophenotypic, morphologic, and clinical features. Angioimmunoblastic T-cell lymphoma (AITL) is the prototypical TFH lymphoma; in addition, the 5th World Health Organization (WHO) and the International Consensus Classification (ICC) recognizes two other unique subtypes: follicular type and not otherwise specified (NOS). TFH lymphomagenesis is largely driven by the stepwise acquisition of somatic mutations with TET2 and DNMT3A mutations occurring early in hematopoietic stem cells. Subsequently, other characteristic mutations such as RHOA and IDH2 (in AITL) are observed. This presentation discusses the morphologic spectrum, immunophenotype, diagnostic mimics/pitfalls, and unique genetic attributes of this category of T-cell lymphomas.

Lecture Presenter
Madhu P. Menon, MD, PhD, FCAP, FASCP
Madhu P. Menon, MD, PhD
Associate Professor, University of Utah School of Medicine
Medical Director, Hematopathology, ARUP Laboratories

Dr. Madhu P. Menon, MD, is a medical director of hematopathology and an associate director professor at the University of Utah School of Medicine. Dr. Menon obtained his medical degree from Baroda Medical College, Maharaja Sayajirao University, and a doctorate degree in molecular medicine from the Huck Institute of Life Sciences, Pennsylvania State University. He then completed his anatomic and clinical pathology residency at the University of Massachusetts Medical School and hematopathology fellowships from the National Institutes of Health/National Cancer Institute, George Washington University Hospital, and Johns Hopkins University Hospital as well as a postdoctoral fellowship at the Maine Medical Center Research Institute. Dr. Menon is board certified in hematopathology, anatomic and clinical pathology. He also has a Lean Silver Certification, LEAN training for healthcare leaders. His research interests include diagnostic and prognostic markers in lymphomas, molecular characterization of lymphomas, and biomarkers for early detection of progression and transformation of low-grade lymphomas.

Objectives

After this presentation, participants will be able to:

Describe the different subtypes of T-follicular helper lymphomas in the context of the ICC and WHO (5) classification schemes
Describe the morphology, immunophenotype, and mutational spectrum of TFH lymphomas
Describe the mimics of TFH lymphomas and key differentiating features