TY - JOUR
T1 - Expression of germinal center cell markers by extranodal marginal zone lymphomas of MALT type within colonized follicles, a diagnostic pitfall with follicular lymphoma
AU - Poveda, Julio
AU - Cassidy, Daniel P.
AU - Zhou, Yi
AU - Alderuccio, Juan Pablo
AU - Lossos, Izidore S.
AU - Vega, Francisco
AU - Chapman, Jennifer
N1 - Publisher Copyright:
© 2020 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2021
Y1 - 2021
N2 - 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.
AB - 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.
KW - Plasticity of protein expression
KW - diagnostic pitfall
KW - dual immunohistochemistry
KW - follicular colonization
KW - marginal zone lymphoma
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U2 - 10.1080/10428194.2020.1855347
DO - 10.1080/10428194.2020.1855347
M3 - Article
C2 - 33283568
AN - SCOPUS:85097204584
SN - 1042-8194
VL - 62
SP - 1116
EP - 1122
JO - Leukemia and Lymphoma
JF - Leukemia and Lymphoma
IS - 5
ER -