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extranodal marginal zone B-cell lymphoma

Monday 5 November 2007

monocytoid B-cell lymphoma, extra-nodal marginal zone lymphoma, extranodal MZBCL, ENMZBCL, extranodal MALT lymphomas


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.


- 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)


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)


- 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