Peripheral T-Cell Lymphomas of Follicular Helper T-Cell Type Frequently Display an Aberrant CD3-/dimCD4+ Population by Flow Cytometry: An Important Clue to the Diagnosis of a Hodgkin Lymphoma Mimic
Alikhan M, Song JY, Sohani AR, Moroch J, Plonquet A, Duffield AS, Borowitz MJ, Jiang L, Bueso-Ramos C, Inamdar K, Menon MP, Gurbuxani S, Chan E, Smith SM, Nicolae A, Jaffe ES, Gaulard P, and Venkataraman G. Peripheral T-cell lymphomas of follicular helper T-cell type frequently display an aberrant CD3-/dimCD4+ population by flow cytometry: an important clue to the diagnosis of a Hodgkin lymphoma mimic. Mod Pathol 2016.
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc
Nodal follicular helper T-cell-derived lymphoproliferations (specifically the less common peripheral T-cell lymphomas of follicular type) exhibit a spectrum of histologic features that may mimic reactive hyperplasia or Hodgkin lymphoma. Even though angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma of follicular type share a common biologic origin from follicular helper T-cells and their morphology has been well characterized, flow cytometry of peripheral T-cell lymphomas of follicular type has not been widely discussed as a tool for identifying this reactive hyperplasia/Hodgkin lymphoma mimic. We identified 10 peripheral T-cell lymphomas of follicular type with available flow cytometry data from five different institutions, including two cases with peripheral blood evaluation. For comparison, we examined flow cytometry data for 8 classical Hodgkin lymphomas (including 1 lymphocyte-rich classical Hodgkin lymphoma), 15 nodular lymphocyte predominant Hodgkin lymphomas, 15 angioimmunoblastic T-cell lymphomas, and 26 reactive nodes. Lymph node histology and flow cytometry data were reviewed, specifically for the presence of a CD3(-/dim)CD4(+) aberrant T-cell population (described in angioimmunoblastic T-cell lymphomas), besides other T-cell aberrancies. Nine of 10 (90%) peripheral T-cell lymphomas of follicular type showed a CD3(-/dim)CD4(+) T-cell population constituting 29.3% (range 7.9-62%) of all lymphocytes. Five of 10 (50%) had nodular lymphocyte predominant Hodgkin lymphoma or lymphocyte-rich classical Hodgkin lymphoma-like morphology with scattered Hodgkin-like cells that expressed CD20, CD30, CD15, and MUM1. Three cases had a nodular growth pattern and three others exhibited a perifollicular growth pattern without Hodgkin-like cells. Epstein-Barr virus was positive in 1 of 10 cases (10%). PCR analysis showed clonal T-cell receptor gamma gene rearrangement in all 10 peripheral T-cell lymphomas of follicular type. By flow cytometry, 11 of 15 (73.3%) angioimmunoblastic T-cell lymphomas showed the CD3(-/dim)CD4(+) population (mean: 19.5%, range: 3-71.8%). Using a threshold of 3% for CD3(-/dim)CD4(+) T cells, all 15 nodular lymphocyte predominant Hodgkin lymphoma controls and 8 classical Hodgkin lymphomas were negative (Mann-Whitney P=0.01, F-PTCL vs Hodgkin lymphomas), as were 25 of 26 reactive lymph nodes. The high frequency of CD3(-/dim)CD4(+) aberrant T cells is similar in angioimmunoblastic T-cell lymphomas and peripheral T-cell lymphomas of follicular type, and is a useful feature in distinguishing peripheral T-cell lymphomas of follicular type from morphologic mimics such as reactive hyperplasia or Hodgkin lymphoma.
Medical Subject Headings
Aged; Aged, 80 and over; CD4-Positive T-Lymphocytes; Diagnosis, Differential; Female; Flow Cytometry; Hodgkin Disease; Humans; Lymphoma, T-Cell, Peripheral; Male; Middle Aged; Retrospective Studies; T-Lymphocyte Subsets