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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== |
| | | |
− | Put your text here
| + | * 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== |