Expression of germinal center cell markers by extranodal marginal zone lymphomas of MALT type within colonized follicles, a diagnostic pitfall with follicular lymphoma

Julio Poveda, Daniel P. Cassidy, Yi Zhou, Juan Pablo Alderuccio, Izidore S. Lossos, Francisco Vega, Jennifer Chapman

Research output: Contribution to journalArticlepeer-review

Abstract

We reviewed 341 consecutive cases of marginal zone lymphoma (MZL) (47) or follicular lymphoma (FL) (294) of which 7 were difficult to distinguish due to perceived coexpression of BCL6 and BCL2 by tumor cells in follicular foci. This stimulated us to develop dual BCL6/BCL2 immunohistochemistry, allowing us to assess coexpression among individual cells. Dual staining confirmed coexpression in 6 of 7 cases, all extranodal MZL (ENMZL) based on overall features and representing 13% of MZL in this series. These findings confirm that MZL cells have plasticity regarding protein expression within the germinal center (GC) microenvironment, an important diagnostic pitfall. Intriguingly, in all MZL expressing BCL6, non-neoplastic GC B cells within colonized follicles showed diminished or absent CD10 expression but preserved BCL6 and high ki67. This finding suggests plasticity of CD10 expression in non-neoplastic GC B cells in the context of colonization by MZL, possibly related to NF-kB dysregulation.

Original languageEnglish (US)
Pages (from-to)1116-1122
Number of pages7
JournalLeukemia and Lymphoma
Volume62
Issue number5
DOIs
StatePublished - 2021

Keywords

  • Plasticity of protein expression
  • diagnostic pitfall
  • dual immunohistochemistry
  • follicular colonization
  • marginal zone lymphoma

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Cancer Research

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