extranodal marginal zone B-cell lymphoma

See also: MALT lymphoma

Digital cases

 HPC:296 : Colonic marginal zone B-cell lymphoma (Colonic MALT lymphoma)
 HPC:317 : Pulmonary marginal zone B-cell lymphoma / pulmonary MALT lymphoma
 HPC:330 : Rectal marginal zone B-cell lymphoma (Rectal MALT lymphoma)
 JRC:15045 : Thyroid MALT lymphoma

Extranodal marginal zone B-cell lymphoma is recognized as a distinct clinicopathologic entity.

Synopsis

 neoplastic marginal zone cells (centrocyte-like cells or monocytoid B cells)

• round to irregular nuclei
• abundant pale cytoplasm

 variable numbers of plasmacytoid and/or plasma cells
 reactive follicles usually present

• monoclonal B cells occupying the marginal zone and/or the interfollicular region
• +/- follicles contain an excess of marginal zone cells (follicular colonization)

 In epithelial tissues the marginal zone cells typically invade the adjacent mucosal or glandular epithelium, forming lymphoepithelial lesions (LEL)

Immunochemistry

The tumor cells express B-cell-associated antigens, are surface immunoglobulin (M > G or A) positive, are immunoglobulin D negative, exhibit monotypic light chain restriction.

Theya are CD5 and CD10 negative.

Plasma cells are often distributed in distinct subepithelial or interfollicular zones, and are monoclonal in up to 40% of cases.

See also

 MALT lymphoma
 mucosa-associated lymphoid tissue (MALT)

References

 Nathwani BN, Mohrmann RL, Brynes RK, Taylor CR, Hansmann ML, Sheibani K. Monocytoid B-cell lymphomas: an assessment of diagnostic criteria and a perspective on histogenesis. Hum Pathol. 1992 Sep;23(9):1061-71. PMID: 1381334

 Shin SS, Sheibani K, Fishleder A, Ben-Ezra J, Bailey A, Koo CH, Burke JS, Tubbs R, Rappaport H. Monocytoid B-cell lymphoma in patients with Sjogren’s syndrome: a clinicopathologic study of 13 patients. Hum Pathol. 1991 May;22(5):422-30. PMID: 18517181