[1474] Peripheral T-Cell Lymphomas of Follicular T-Helper (TFH) Cell Derivation with Hodgkin/Reed Sternberg Cells of B-Cell Lineage: Both EBV-Positive and EBV-Negative Variants Exist

Alina Nicolae, Stefania Pittaluga, Girish Venkataraman, Anahi Vijnovich-Baron, Liqiang Xi, Mark Raffeld, Elaine S Jaffe. National Cancer Institute, Bethesda, MD; Loyola University Medical Center, Maywood, IL; Centro de Patología CEPACIT, Buenos Aires, Argentina

Background: Peripheral T-cell lymphomas (PTCL) are functionally and morphologically complex. EBV-positive B-cells have been reported in angioimmunoblastic T-cell lymphoma (AITL) and other PTCL and may mimic Hodgkin/Reed Sternberg (HRS) cells, but EBV-negative HRS-like B-cells have not been described. We wished to assess the spectrum of PTCL associated with HRS-like cells, and to determine if EBV-negative HRS-like cells may be seen.
Design: Fifty seven PTCL cases reported as containing HRS-like cells of B-cell lineage were identified in the Hematopathology archives from 1999 to present. Available clinical, histologic, immunophenotypic and molecular data (IG and TCR gamma gene rearrangements) were analyzed. The immunohistochemical panel included CD20, CD3, CD4, CD8, CD10, CD15, CD30, CD21, CD79a, PAX5, Oct2, BOB.1, BCL6, MUM1, PD-1, kappa, lambda and LMP1. All cases were tested for EBV by in situ hybridization (EBER) and/or LMP1.
Results: All patients were adults, median age 63, and presented with lymphadenopathy. The male:female ratio was 31:26 (1.2:1). The 57 cases included 32 AITL, 19 PTCL-NOS, 3 PTCL-NOS, follicular variant, 1 PTCL-NOS, T-zone variant and 2 adult T-cell leukemia/lymphoma. 26% of PTCL-NOS (5/19) expressed TFH-cell markers, but lacked classical features of AITL or PTCL-NOS, follicular variant. Clonal TCR rearrangement was detected in 46/53 cases. 6/38 cases had a concomitant clonal IG gene rearrangement. In 52/57 cases the HRS-like cells were positive for EBV. 5 cases, 3 AITL and 2 PTCL-NOS, follicular variant, contained HRS-like cells negative for EBV. All PTCL with EBV-negative HRS-like cells had a TFH-immunophenotype. The neoplastic T-cells expressed CD3, CD4, CD10 and PD-1, and formed rosettes around the HRS-like cells. The HRS-like cells were positive for CD20 and PAX5 with variable intensity, CD30 (5/5) and CD15 (4/5).
Conclusions: Both EBV-positive and EBV-negative HRS-like B-cells may occur in the background of PTCL; caution is needed to avoid misdiagnosis as CHL. The close interaction between the HRS-like cells and the rosetting PD-1-positive T-cells suggests a possible pathogenetic role in this phenomenon, and provides new insights into the abnormal B-cell proliferations that occur in the context of TFH malignancies.
Category: Hematopathology

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 272, Tuesday Afternoon


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