HAEM5:Primary cutaneous marginal zone lymphoma: Difference between revisions
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*Predominantly affects adults in the fifth and sixth decades of life | *Predominantly affects adults in the fifth and sixth decades of life | ||
*Male preponderance | *Male preponderance | ||
*Unknown etiology in most cases | *Unknown etiology in most cases | ||
*Possible causes include chronic antigenic stimulation by intradermally applied antigens (e.g. tattoo pigments, vaccines, tick-borne bacteria, etc.) | *Possible causes include chronic antigenic stimulation by intradermally applied antigens (e.g. tattoo pigments, vaccines, tick-borne bacteria, etc.) | ||
*Association with ''Borrelia burgdorferi'' infection in endemic Europe but not associated in USA or Asia | *Association with ''Borrelia burgdorferi'' infection in endemic Europe but not associated in USA or Asia | ||
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==Morphologic Features== | ==Morphologic Features== | ||
* Dense dermal infiltrate composed of: | *Dense dermal infiltrate composed of: | ||
** Small lymphocytes | **Small lymphocytes | ||
** Plasma cells | **Plasma cells | ||
*** Located at periphery of lymphoid infiltrates or in subepidermal compartment | ***Located at periphery of lymphoid infiltrates or in subepidermal compartment | ||
*** Heavy chain immunophenotype show different morphologies: | ***Heavy chain immunophenotype show different morphologies: | ||
**** Non-class-switched forms | ****Non-class-switched forms | ||
***** Sheets of B-lymphocytes and few T-lymphocytes | *****Sheets of B-lymphocytes and few T-lymphocytes | ||
***** Scattered plasma cells | *****Scattered plasma cells | ||
**** Class-switched forms | ****Class-switched forms | ||
***** Large number of reactive T-lymphocytes but can occasionally be obscured by the neoplastic B cells | *****Large number of reactive T-lymphocytes but can occasionally be obscured by the neoplastic B cells | ||
***** Peripherally clustered monotypic plasma cells | *****Peripherally clustered monotypic plasma cells | ||
** Follicles with reactive germinal centers (most cases) | **Follicles with reactive germinal centers (most cases) | ||
** clusters of plasmacytoid dendritic cells at periphery of infiltrates | **clusters of plasmacytoid dendritic cells at periphery of infiltrates | ||
==Immunophenotype== | ==Immunophenotype== | ||
* Neoplastic B cells have the following immunophenotype: | *Neoplastic B cells have the following immunophenotype: | ||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
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|Negative||BCL6 | |Negative||BCL6 | ||
|- | |- | ||
|Negative | |Negative | ||
|Cyclin D1 | |Cyclin D1 | ||
|} | |} | ||
* The reactive germinal centers B cells are BCL6 positive and BCL2 negative. | *The reactive germinal centers B cells are BCL6 positive and BCL2 negative. | ||
* CD123 positive plasmacytoid dendritic cells. | *CD123 positive plasmacytoid dendritic cells. | ||
* Plasma cells have monotypic expression of immunoglobulin light chains often. Heavy chain class-switched form IgG, IgA, or IgE and have no expression of CXCR3. If non-class-switched forms are present, IgM and CXCR3 are expressed. | *Plasma cells have monotypic expression of immunoglobulin light chains often. Heavy chain class-switched form IgG, IgA, or IgE and have no expression of CXCR3. If non-class-switched forms are present, IgM and CXCR3 are expressed. | ||
** Approximately 90% of cases have IgG, IgA, or IgE positivity | **Approximately 90% of cases have IgG, IgA, or IgE positivity | ||
** Approximately 10% of cases have IgM positivity | **Approximately 10% of cases have IgM positivity | ||
* IgG4 expressed by plasma cells in 13-35% of cases, though not related to IgG4-related disease. | *IgG4 expressed by plasma cells in 13-35% of cases, though not related to IgG4-related disease. | ||
==Chromosomal Rearrangements (Gene Fusions)== | ==Chromosomal Rearrangements (Gene Fusions)== | ||
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|''FAS'' (CD95) gene mutation | |''FAS'' (CD95) gene mutation | ||
|Apoptosis regulator | |Apoptosis regulator | ||
|>60% of cases | |>60% of cases | ||
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==Additional Information== | ==Additional Information== | ||
* Favorable prognosis | |||
** 5-year disease-specific survival rate >98% | |||
* Recurrence is common | |||
* 4% of patients will have extracutaneous spread, particularly in patients with longstanding multifocal disease | |||
==Links== | ==Links== | ||