Nodal Marginal Zone B-cell Lymphoma



Nodal Marginal Zone B-cell Lymphoma


Pei Lin, MD





Key Facts


Clinical Issues



  • Age: 5th-6th decades


  • No evidence of extranodal or splenic lymphoma


  • Can transform to diffuse large B-cell lymphoma


Microscopic Pathology



  • Expanded marginal zones or replacement of lymph node by small cells with scattered large cells


  • Small cells can be centrocyte-like or monocytoid


  • Lymphoplasmacytoid or mature-appearing plasma cells can be prominent


  • Residual reactive follicles with hyperplastic germinal centers


Ancillary Tests



  • Positive for monotypic Ig (bright) and B-cell markers



    • In paraffin sections, only plasmacytoid cells express cytoplasmic Ig


  • Aberrantly express CD43 in ˜ 50% of cases


  • Usually negative for CD5, CD10, and CD23


Top Differential Diagnoses



  • MALT lymphoma secondarily involving lymph node


  • Lymphoplasmacytic lymphoma


  • Mantle cell lymphoma


  • CLL/SLL with plasmacytoid differentiation


  • Peripheral T-cell lymphoma


Diagnostic Checklist



  • Often pale appearance at low-power magnification


  • Residual germinal centers surrounded by centrocyte-like and monocytoid cells


  • Scattered large cells present







Nodal marginal zone lymphoma. The architecture is altered by nodules composed of central darker areas (germinal centers) image surrounded by peripheral pale areas (marginal zone areas) image.






A residual germinal center image with tingible body macrophages image is surrounded by lymphoma cells with pale cytoplasm expanding marginal zones and interfollicular areas image.


TERMINOLOGY


Abbreviations



  • Nodal marginal zone B-cell lymphoma (NMZL)


Synonyms



  • Nodal marginal zone lymphoma


  • Monocytoid B-cell lymphoma


  • Parafollicular B-cell lymphoma


  • NMZL can be placed in any of 3 categories depending on large cell number (Working Formulation [1982])



    • Small lymphocytic plasmacytoid, diffuse small cleaved cell, or diffuse mixed small and large cell


Definitions



  • Primary nodal B-cell lymphoma histologically resembling lymph nodes involved by MZL of extranodal or splenic types



    • There can be no evidence of extranodal or splenic disease


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Low, ˜ 2% of all non-Hodgkin lymphomas


  • Age



    • 5th-6th decades



      • Median age around 60 years


      • Can occur in children


  • Gender



    • Female predominance


Presentation



  • Lymphadenopathy, localized or widespread



    • Systemic (B) symptoms in 1/3 of patients


    • In patients with localized disease, head and neck region is most often affected


    • Bone marrow involvement common (30-60% of patients in various studies)


    • Leukemic involvement (elevated WBC) is uncommon


    • Association with hepatitis C infection in Italy


Prognosis



  • Clinically indolent



    • > 60% of patients have overall survival > 5 years


    • Affected children have excellent long-term survival


  • Patients can undergo transformation to diffuse large B-cell lymphoma



    • Prognosis substantially worse


MICROSCOPIC PATHOLOGY


Histologic Features



  • Lymph nodes can be partially or completely effaced by lymphoma



    • Marginal zones expanded in cases with partial involvement


    • Neoplasm has diffuse pattern in completely replaced lymph nodes


  • Cytologically, predominant cell type is small with variably irregular nuclear contours



    • Lymphoma cells commonly have abundant pale cytoplasm (so-called monocytoid features)


    • Lymphoid cells with plasmacytoid differentiation or plasma cells are common and can be numerous


    • Large cells are always present in varying numbers; can be numerous


  • Residual reactive follicles with hyperplastic germinal centers are common



    • Germinal centers often have numerous tingible body macrophages


    • Reactive follicles can be colonized by lymphoma (mimicking follicular lymphoma)


  • Bone marrow shows paratrabecular and nonparatrabecular pattern of involvement




    • Lymphoma aggregates often associated with follicular dendritic cells, CD21(+)


Predominant Pattern/Injury Type



  • Lymphoid, marginal zone


Predominant Cell/Compartment Type



  • Centrocyte-like or monocytoid cells, lymphoplasmacytoid cells or plasma cells


ANCILLARY TESTS


Immunohistochemistry



  • Neoplastic plasmacytoid lymphocytes and plasma cells express monotypic cytoplasmic Ig light chain


  • Aberrant expression of CD43 is common (˜ 50%)


  • Positive for pan-B-cell antigens (e.g., CD19, CD20, pax-5)


  • Bcl-2(+), CD10(-), Bcl-6(-), Cyclin-D1(-)


  • Usually negative for CD5 and CD23


Flow Cytometry



  • Usually express monotypic surface Ig


  • Brightly positive for pan-B-cell antigens (CD19, CD20, CD22) and negative for CD10


  • Negative for T-cell antigens (CD2, CD3, CD5, CD7, TCR-β)


  • CD43 is commonly expressed


  • Subset of cases can be CD23(+)



    • Rare cases can be CD5(+)


Cytogenetics



  • No consistent translocations identified


  • Trisomies of 3, 7, and 18 in subset of cases


PCR



  • Ig gene rearrangements are present


  • Ig genes are commonly mutated



    • May result in false-negative PCR results


  • No evidence of BCL1/IgH or IgH/BCL2 translocations


DIFFERENTIAL DIAGNOSIS


Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue (MALT Lymphoma)

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Nodal Marginal Zone B-cell Lymphoma

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