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HAEM5:Primary cutaneous marginal zone lymphoma (view source)
Revision as of 16:22, 6 May 2024
, 6 May→Additional Information
*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
==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"
|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)==
|''FAS'' (CD95) gene mutation
|''FAS'' (CD95) gene mutation
|Apoptosis regulator
|Apoptosis regulator
|>60% of cases
|>60% of cases
|
|
|
|
==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==