Marginal zone B-cell lymphoma: a retrospective immunophenotypic analysis.
BACKGROUND
Marginal zone B-cell lymphoma (MZL) comprises three related yet biologically distinct subtypes--splenic MZL (SMZL), nodal MZL (NMZL), and extranodal MZL of MALT type (MALT). In cases without adequate morphology, immunophenotypic characterization by flow cytometric immunophenotyping (FCI) relies heavily on exclusion of other low-grade lymphomas. We performed a retrospective review of FCI studies of MZL to search for immunophenotypes specific for MZL and its subtypes. We compared these to follicular lymphoma (FL) as we were specifically interested in differentiating MZL from CD10 negative FL.


METHODS
FCI findings for MZL and FL cases were reviewed. Statistical analysis of patterns and intensity of antigen expression [mean channel fluorescence (MCF)] were performed.


RESULTS
Thirty-one cases of MZL (7 SMZL, 6 NMZL, 15 MALT, 3 MZL not otherwise specified) and 31 cases of FL were identified. All expressed CD19, CD20, and CD45. Thirty-two percent of MZL and 77% of FL expressed CD38. Expression of CD11c was seen in 57% of SMZL and 8% of other MZL (P < 0.01). Statistically significant differences in antigen expression between MZL and FL were seen for CD10, CD11c, and CD38. CD19 expression was significantly brighter in MZL (mean MCF of 455.3) than in FL (mean MCF of 166.9) (P < 0.001). MCF for isotype controls and CD20 were similar for FL and MZL.


CONCLUSIONS
MZL expresses typical pan-B-cell antigens. Expression of CD11c is highly associated with SMZL. Levels of CD19 expression in conjunction with CD11c and CD38 expression can distinguish MZL from CD10 negative FL.
Kost
Christine B
CB
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
Holden
Jeannine T
JT
Mann
Karen P
KP
D000912:Antibodies, Neoplasm / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D005453:Fluorescence; D006801:Humans; D016130:Immunophenotyping / Q000379:methods*; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis* / Q000276:immunology; D008224:Lymphoma, Follicular / Q000276:immunology; D012189:Retrospective Studies
D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm