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marginal zone B-cell lymphoma

Tuesday 6 April 2004

MZBCL, marginal zone B-cell lymphoma, MZL; MALT lymphoma

PO

Definition: Marginal zone lymphomas (MZL) are indolent B-cell lymphomas that represent less than 20% of all lymphomas.

When marginal zone lymphomas involve the lymph nodes they are called "nodal marginal zone B-cell lymphomas" (NMZLs) whereas when they involve places outside the lymph nodes (gastrointestinal tract, thyroid, breast, or skin) they are called "mucosa-associated lymphatic tissue lymphomas" (MALT lymphomas or MALTomas).

The "splenic marginal zone lymphomas" (SMZLs) are considered a third separate subtype.

Digital cases

- HPC:296 : Colonic MALT lymphoma
- HPC:299 : Marginal zone B-cell lymphoma of the spleen
- HPC:304 : gastric MALT lymphoma / gastric marginal zone lymphoma (mucosal biopsies)
- HPC:306 : Thyroid marginal zone B-cell lymphoma (Thyroid MALT lymphoma) and lymphocytic thyroiditis
- HPC:312 - Nodal localization of a marginal zone B-cell lymphoma (MZBCL) (nodal localization of a MALT lymphoma)
- HPC:319 : Gastric MALT lymphoma / Gastric marginal zone lymphoma (fundic mucosal biopsies)

Localization

- nodal marginal zone B-cell lymphoma
- splenic marginal zone B-cell lymphoma
- extra-nodal marginal zone B-cell lymphoma (MALT lymphoma)

Immunophenotype

- pan-B+: CD20+, CD19+
- BCL2+/- variable
- CD10-
- CD23-
- CD11c+/- variable

- CD3-
- CD5-/+ variable

- cyIg + (40% of the cells)
- sIgM+ bright- sIgD-

Putative cell of origin: Marginal zone lymphocytes harbouring hypermutated IgV genes

Differential diagnosis

- CLL/SLL: CD5+, CD23+
- follicular lymphoma : CD10+
- mantle cell lymphoma : CD5+
- reactive lymphadenitis or lymphoid nodule : lack destructive / infiltrative pattern of extrafollicular B-cells demonstrated by CD21/CD35 (staining follicular dendritic cells)
- also inflammatory pseudotumor, rhabdomyomas if tumors contain crystalline inclusions (Arch Pathol Lab Med 2000;124:460)

Cytogenetics

- t(11;18)(q21;q21) (API2-MALT1 fusion gene) (30-50% of the low-grade MALT)
- t(1;14)(p21;q32) in extra-nodal MALT lymphoma
- t(14;18)
- t(3;14)
- del(7)(q22-31) in splenic MZBCL (40% of the cases)
- trisomy 3 (7718871) and +3q (30-70% of the cases) in nodal, extra-nodal and splenic MZBCL
- trisomy 12 , trisomy 18

Molecular biology

- TP53 mutations / LOH

CGH (17492759)

- losses

  • 6q23.3 loss (38%)
  • 7q36.3 loss (8%)
  • 13q34 loss (8%)

- gains

  • Chr.3 gain (38%),
  • Chr.15 gain (16%)
  • 18q gain (16%)
  • 6p gain (8%)

See also

- marginal zone B cell lymphoma

References

- Kim WS, Honma K, Karnan S, Tagawa H, Kim YD, Oh YL, Seto M, Ko YH. Genome-wide array-based comparative genomic hybridization of ocular marginal zone B cell lymphoma: Comparison with pulmonary and nodal marginal zone B cell lymphoma. Genes Chromosomes Cancer. 2007 May 10;46(8):776-783 PMID: 17492759

- Isaacson PG, Du MQ. MALT lymphoma: from morphology to molecules. Nat Rev Cancer. 2004 Aug;4(8):644-53. PMID: 15286744

- Taddesse-Heath L, Pittaluga S, Sorbara L, Bussey M, Raffeld M, Jaffe ES. Marginal zone B-cell lymphoma in children and young adults. Am J Surg Pathol. 2003 Apr;27(4):522-31. PMID: 12657939