Changes

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==Definition / Description of Disease==

==Definition / Description of Disease==

An indolent primary cutaneous CD4+ T-cell lymphoproliferative disorder for which conservative treatment such as excision and local radiation is known to be effective.

An indolent primary cutaneous CD4+ T-cell lymphoproliferative disorder for which conservative treatment such as excision and local radiation is known to be effective. They express at least one follicular T-helper (TFH) marker, except for CD10, and thus is suspected to arise from TFH cells. 

Primary cutaneous CD4+ small/medium T-cell lymphoma (not preferred due to indolent clinical course)<ref name=":0">Swerdlow, S.H.  et al. WHO classification of tumours of haematopoietic and lymphoid tissues (4th Ed), pp.401</ref>

Primary cutaneous CD4+ small/medium T-cell lymphoma (not preferred due to indolent clinical course)<ref name=":0">Swerdlow, S.H.  et al. WHO classification of tumours of haematopoietic and lymphoid tissues (4th Ed), pp.401</ref>

==Epidemiology / Prevalence==

==Epidemiology / Prevalence==

Rare disease, comprising approximately 2-3% of all cutaneous lymphomas. <ref name=":0" />

Previously considered an uncommon disease but may be underestimated.

 

Comprising up to 6% of cutaneous T-cell lymphomas (CTCLs). <ref>{{Cite journal|last=Willemze|first=Rein|last2=Cerroni|first2=Lorenzo|last3=Kempf|first3=Werner|last4=Berti|first4=Emilio|last5=Facchetti|first5=Fabio|last6=Swerdlow|first6=Steven H.|last7=Jaffe|first7=Elaine S.|date=2019-04-18|title=The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas|url=https://pubmed.ncbi.nlm.nih.gov/30635287/|journal=Blood|volume=133|issue=16|pages=1703–1714|doi=10.1182/blood-2018-11-881268|issn=1528-0020|pmc=6473500|pmid=30635287}}</ref>

 

One study reported local prevalence of 12.5% of all CTCLs, making it the second most common cutaneous lymphoma following mycosis fungoides.<ref name=":1" />

==Clinical Features==

==Clinical Features==

Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span>

Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span>

*Tends to extend to subcutaneous tissue<ref name=":3" /><ref name=":2" />

*Tends to extend to subcutaneous tissue<ref name=":3" /><ref name=":2" />

*Lack significant epidermotropism and folliculotropism<ref name=":3" />

*Lack significant epidermotropism and folliculotropism<ref name=":3" />

*Predominantly small/medium-size T-cells with pleomorphism<ref name=":3" /><ref name=":2" /><ref name=":1" /><ref name=":0" />

*Predominantly small/medium-size T-cells with mild-moderate cytological atypia<ref name=":3" /><ref name=":2" /><ref name=":1" /><ref name=":0" />

*Low number of large lymphocytes allowed (<30%)<ref name=":0" /><ref name=":2" /><ref name=":3" />

*Low number of large lymphocytes allowed (<30%)<ref name=":0" /><ref name=":2" /><ref name=":3" />

*Can have mixed background containing CD8+ T-cells, B-cells, plasma cells, histiocytes, +/-multinucleated giant cells or granulomatous change<ref name=":3" /><ref name=":2" />

*Can have mixed background containing CD8+ T-cells, B-cells, plasma cells, histiocytes, +/-multinucleated giant cells or granulomatous change<ref name=":3" /><ref name=":2" />

*Absent/few eosinophils<ref name=":3" />

*Absent/few eosinophils<ref name=":3" />

*Low proliferation rate; Ki67 <20%<ref name=":1" /><ref name=":0" />

*Low proliferation rate; Ki67 <20%<ref name=":1" /><ref name=":0" />

*By definitive, excludes cases that fit the diagnostic criteria for mycosis fungoides<ref name=":0" /><br />

*By definitive, excludes cases that meet the diagnostic criteria for mycosis fungoides<ref name=":0" /><br />

==Immunophenotype==

==Immunophenotype==

!Notes

!Notes

|-

|-

|<span class="blue-text">EXAMPLE:</span>

|N/A

|N/A

|<span class="blue-text">EXAMPLE:</span> Yes

|N/A

|<span class="blue-text">EXAMPLE:</span> No

|N/A

|<span class="blue-text">EXAMPLE:</span> No

|N/A

|<span class="blue-text">EXAMPLE:</span>

|}

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==Gene Mutations (SNV / INDEL)==

==Gene Mutations (SNV / INDEL)==

!Notes

!Notes

|-

|-

|<span class="blue-text">EXAMPLE:</span> ''TP53''; Variable LOF mutations

|Not found

|N/A

 

|N/A

|N/A

 

|N/A

|N/A

|<span class="blue-text">EXAMPLE:</span> TSG

|N/A

|<span class="blue-text">EXAMPLE:</span> 20% (COSMIC)

|N/A

<span class="blue-text">EXAMPLE:</span> 30% (add Reference)

|N/A

|<span class="blue-text">EXAMPLE:</span> ''IDH1'' R123H

|<span class="blue-text">EXAMPLE:</span> ''EGFR'' amplification

|<span class="blue-text">EXAMPLE:</span> Yes

|<span class="blue-text">EXAMPLE:</span> No

|<span class="blue-text">EXAMPLE:</span> No

|<span class="blue-text">EXAMPLE:</span> Excludes hairy cell leukemia (HCL) (add reference).

|}Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

|}Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

==Epigenomic Alterations==

==Epigenomic Alterations==

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==Genetic Diagnostic Testing Methods==

==Genetic Diagnostic Testing Methods==

==Familial Forms==

==Familial Forms==

<span style="color:#0070C0">N/A </span>

<span style="color:#0070C0">N/A </span>