Reactive Bcl2-positive germinal centres in paediatric tonsils: expanding the spectrum of lymphoma mimickers in children and adolescents.

in Histopathology by Marco Pizzi, Luisa Lorenzi, Federico Scarmozzino, Emma Albertini, Piera Balzarini, Marta Sbaraglia, Luisa Santoro, Mariella Chiudinelli, Lara Mussolin, Elisa Carraro, Cesare Cutrone, Stefano Casola, Vilma Pellegrini, Silvia Nalio, Laura Bonaldi, Marta Pillon, Angelo Paolo Dei Tos

TLDR

  • Bcl2-positive GCs are a rare and benign phenomenon in PCT, mimicking paediatric lymphomas.
  • The study highlights the importance of considering Bcl2-positive GCs in differential diagnosis, expanding the spectrum of lymphoma-mimicking paediatric RLH.

Abstract

Bcl2-positive germinal centres (GCs) have never been documented in reactive lymphoid hyperplasia (RLH). Here we describe such phenomenon in paediatric chronic tonsillitis (PCT), addressing the differential diagnosis with paediatric lymphomas. Six PCT cases with Bcl2-positive GCs were retrieved from a retrospective series of 166 tonsillectomies from children and adolescents. Clinical-pathological data were collected, also considering the status of IG rearrangements and BCL2 translocations. PCT with Bcl2-positive GCs mostly occurred in males (5/6 cases; median age: 5 years). Histologically, tonsil architecture was preserved and Bcl2 positivity was documented in a minority of GCs. Bcl2-positive GCs expressed CD10 and Bcl6 and had a high proliferation index. All cases had polyclonal IG rearrangements without evidence of monotypic kappa and lambda chains by RNAscope. BCL2 translocations were lacking in all the cases. Bcl2-positive GCs in PCT are a rare and benign phenomenon, expanding the spectrum of lymphoma-mimicking paediatric RLH.

Overview

  • The study describes the phenomenon of Bcl2-positive germinal centre (GCs) in paediatric chronic tonsillitis (PCT) for the first time.
  • The researchers retrospectively analyzed 166 tonsillectomy samples from children and adolescents and identified 6 cases with PCT and Bcl2-positive GCs.
  • The study aims to address the differential diagnosis with paediatric lymphomas and provide a better understanding of this rare and benign phenomenon.

Comparative Analysis & Findings

  • Bcl2-positive GCs were found in a minority of GCs in the tonsils, with preserved tonsil architecture and a high proliferation index.
  • The cells expressed CD10 and Bcl6, had polyclonal IG rearrangements, and lacked BCL2 translocations.
  • The study found that Bcl2-positive GCs in PCT occur mostly in males (5/6 cases) with a median age of 5 years, expanding the spectrum of lymphoma-mimicking paediatric reactive lymphoid hyperplasia (RLH).

Implications and Future Directions

  • This study highlights the importance of considering Bcl2-positive GCs in the differential diagnosis of paediatric lymphomas, particularly in cases of PCT.
  • Future studies should aim to investigate the underlying mechanisms and clinical significance of Bcl2-positive GCs in PCT.
  • The findings of this study underscore the need for further research to better understand the spectrum of lymphoma-mimicking paediatric RLH and to develop more effective diagnostic and therapeutic strategies.
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