Classifications of cutaneous lymphomas and lymphoproliferative disorders: An update from the EORTC cutaneous lymphoma histopathology group.

The classification of primary cutaneous lymphomas and lymphoproliferative disorders (LPD) is continuously evolving by integrating novel clinical, pathological and molecular data. Recently two new classifications for haematological malignancies including entities of cutaneous lymphomas were proposed: the 5th edition of the WHO classification of haematolymphoid tumours and the International Consensus Classification (ICC) of mature lymphoid neoplasms. This article provides an overview of the changes introduced in these two classifications compared to the previous WHO classification. The main changes shared by both classifications include the downgrading of CD8+ acral T-cell lymphoma to CD8+ acral T-cell LPD, and the recognition of entities that were previously categorized as provisional and have now been designated as definite types including primary cutaneous small or medium CD4+ T-cell LPD, primary cutaneous gamma/delta T-cell lymphoma, primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, Epstein-Barr virus-positive mucocutaneous ulcer. Both classifications consider primary cutaneous marginal zone B-cell clonal neoplasm as an indolent disease but use a different terminology: primary cutaneous marginal zone lymphoma (WHO) and primary cutaneous marginal zone LPD (ICC). The 5th WHO classification further introduces and provides essential and desirable diagnostic criteria for each disease type and includes chapters on reactive B- or T-cell rich lymphoid proliferations formerly referred as cutaneous pseudolymphomas, as well as histiocyte and CD8 T-cell rich LPD in patients with inborn error of immunity. As already emphasized in previous lymphoma classifications, the importance of integrating clinical, histological, phenotypic and molecular features remains the crucial conceptual base for defining cutaneous (and extracutaneous) lymphomas.

Diagnosis and Management of Cutaneous Lymphomas Including Cutaneous T-cell Lymphoma.

The cutaneous lymphomas are malignancies of T-cell and B-cell lymphocytes in which the skin is the primary organ of involvement. The cutaneous T-cell lymphomas include variants that can mimic the presentation of common skin diseases or arthropod bites. Mycosis fungoides, the most common cutaneous T-cell lymphoma, usually presents as fixed asymptomatic patches or plaques in sun-protected areas. The cutaneous B-cell lymphomas have fewer variants that often present as papules or nodules that can mimic nonmelanoma skin cancers. Some therapies for cutaneous lymphoma have unique side effects such as central hypothyroidism, hyperlipidemia, and peripheral neuropathy.

Management of primary cutaneous lymphomas during the COVID-19 pandemic.

Primary cutaneous lymphomas are defined as a heterogenic group of T- and B-cell non-Hodgkin lymphomas that present initially in the skin. Patients with primary cutaneous lymphomas are at a higher risk for developing complications in case of infection with the novel coronavirus severe acute respiratory syndrome coronavirus 2. The coronavirus disease 2019 (COVID-19) pandemic has affected the established diagnostic approach, staging, and therapeutic guidelines in patients with primary cutaneous lymphomas. In the light of the current global health crisis, management of primary cutaneous lymphomas needs to be adjusted. The key to achieving this is to balance the optimal control of the lymphoma, with a minimal increase of the personal risk for COVID-19 exposure and complications.

Solitary CD8-Positive Primary Cutaneous Peripheral T-Cell Lymphoma: A Question of Classification.

ABSTRACT: Acral CD8(+) lymphoma is a provisional entity in the latest edition of the WHO Lymphoma Classification and is associated with a highly specific dot-like pattern of immunohistochemical expression of CD68. We report a case of an ulcerated solitary cutaneous lesion arising on the forehead of an adult man, which had a CD8(+) cytotoxic phenotype and areas of dot-like CD68 positivity, but with a number of features that significantly detracted from the classically described acral CD8(+) lymphoma. The nosological status of the lesion is discussed with respect to a preferred diagnosis of peripheral T-cell lymphoma, not otherwise specified.

The clinico-pathological spectrum of primary cutaneous lymphoma other than mycosis fungoides/Sezary syndrome.

The major aim of Session 1 of the 2018 European Association of Hematopathology/Society for Hematopathology Workshop was to collect examples of cutaneous lymphomas, excluding mycosis fungoides/Sezary syndrome, as defined in the current WHO classification of tumours of the haemetopoietic and lymphoid tissues. Overall 42 cases were submitted. These were considered in four main categories: primary cutaneous B cell lymphomas (12 cases), primary cutaneous T cell lymphomas/lymphoproliferations with CD8+/cytotoxic phenotype (12 cases), primary cutaneous CD30-positive lymphoproliferative disorders (15 cases) and primary cutaneous T cell lymphomas/leukaemias with CD4+ phenotype (4 cases). Using these cases as examples, we were able to present the full spectrum of cutaneous lymphoproliferations (excluding mycosis fungoides/Sezary syndrome), including examples of rare, provisional and new entities as listed in the 2017 update of the WHO classification. The findings are summarized in this report with emphasis on differential diagnostic considerations and the importance of clinico-pathological correlation for final subtyping. In presenting these findings we hope to raise awareness of this enigmatic group of neoplasms and to further our understanding of these rare disease entities.

Overview of Cutaneous T-Cell Lymphomas.

Non-Hodgkin's lymphoma (NHL) encompasses a diverse collection of systemic and primary cutaneous lymphomas. Cutaneous T-cell lymphomas (CTCLs) represent about 13% of all NHLs, which are further subdivided into a heterogeneous group with vastly different presentations and histologic features. Diagnosis requires integration of clinical, pathologic, and molecular features. Among CTCLs, mycosis fungoides and Sézary syndrome are the most prevalent. Treatment is aimed at limiting morbidity and halting disease progression. Hematopoietic stem cell transplantation is the only therapy with curative intent.

The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas.

Primary cutaneous lymphomas are a heterogeneous group of T- and B-cell lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. The 2005 World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) consensus classification has served as a golden standard for the diagnosis and classification of these conditions. In September 2018, an updated version of the WHO-EORTC was published in the fourth edition of the WHO Classification of Skin Tumours Blue Book. In this classification, primary cutaneous acral CD8+ T-cell lymphoma and Epstein-Barr virus positive (EBV+) mucocutaneous ulcer are included as new provisional entities, and a new section on cutaneous forms of chronic active EBV disease has been added. The term "primary cutaneous CD4+ small/medium T-cell lymphoma" was modified to "primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder" because of its indolent clinical behavior and uncertain malignant potential. Modifications have also been made in the sections on lymphomatoid papulosis, increasing the spectrum of histologic and genetic types, and primary cutaneous marginal zone lymphomas recognizing 2 different subtypes. Herein, the characteristic features of these new and modified entities as well as the results of recent molecular studies with diagnostic, prognostic, and/or therapeutic significance for the different types of primary cutaneous lymphomas are reviewed. An update of the frequency and survival of the different types of primary cutaneous lymphomas is provided.

Cutaneous T-cell lymphomas in the revised 4th edition of World Health Organization classification of tumors of hematopoietic and lymphoid tissues (2017)

Abstract: Recently, the World Health Organization published the revised 4th edition of its classification of tumors of hematopoietic and lymphoid tissues. The present paper is a concise comparative review of the main primary cutaneous T-cell hematopoietic tumors, with emphasis on their immunohistochemical profiles.

Cutaneous T-cell lymphomas in the revised 4th edition of World Health Organization classification of tumors of hematopoietic and lymphoid tissues (2017).

Recently, the World Health Organization published the revised 4th edition of its classification of tumors of hematopoietic and lymphoid tissues. The present paper is a concise comparative review of the main primary cutaneous T-cell hematopoietic tumors, with emphasis on their immunohistochemical profiles.

[Primary cutaneous lymphoma-a case series of 163 patients]. / Primär kutane Lymphome ­ eine Fallserie von 163 Patienten.

BACKGROUND: In addition to a broad and clinically diverse spectrum of known primary cutaneous lymphomas, for which an incidence of 1-3:100,000 is postulated, each year further entities are specified and defined. The goal is the presentation of a case series from daily clinical routine. METHODS: Over a period of 6 years and 2 months, patients consulting the Department of Dermatology, Medical Center University of Freiburg, were registered. Subsequently, collectives of mycosis fungoides (MF), Sezary syndrome (SS), CD30+ lymphoproliferative diseases, single cases with rare primary cutaneous lymphomas, and subcollectives of B­cell lymphomas were examined. The high number of MF cases allowed the additional quantitative analyses of the types of therapies used in this group. RESULTS: Yearly 16-25 new diagnoses of primary cutaneous lymphoma are made. The evaluation of 163 primary cutaneous lymphoma revealed 111 cases with MF (68.1%), including 9 particular variants, 15 primary cutaneous CD30+ lymphoproliferative diseases (9.2%) dominated by 10 lymphomatoid papulosis (LyP), in addition to 5 primary cutaneous anaplastic large cell lymphoma (PCALCL), 6 SS (3.68%), and 24 cutaneous B­cell lymphomas (14-72%). Three cases with rare primary cutaneous T/NK cell lymphomas are addressed in detail. In all, 82% of MF cases were stage IA and IB. The descending use of therapies for stage I-III included steroids and diverse UV therapies followed by bexarotene, interferon-α, methotrexate, and extracorporal photophoresis. CONCLUSIONS: Diagnoses of cutaneous lymphomas belong to a vast spectrum of differential diagnoses. This registry describes frequent findings and shows rare variants. You can only diagnose what you know; accordingly, a collection of case reports, which we wish to encourage, can help in processing and specification of entities.

[Treatment of rare cutaneous T­cell lymphoma and blastic plasmacytoid dendritic cell neoplasm]. / Therapie seltener kutaner T­Zell-Lymphome und der blastären plasmazytoiden dendritischen Zellneoplasie.

Among the group of primary cutaneous lymphomas several subtypes have very low incidence rates. Based on the revision of the WHO classification for lymphoid neoplasms (2016), an overview of rare cutaneous T­cell lymphoma (CTCL) subtypes is given and therapeutic approaches are detailed. The prognosis of the different subtypes is highly variable underlining the importance of adequate stage and subtype adapted treatment. In cases of indolent subtypes topical treatment, e. g. topical corticosteroids or UV phototherapy are often sufficient. For aggressive variants, early discussion of more aggressive systemic treatment options is warranted.

Cutaneous intravascular natural killer/T cell lymphoma with peculiar immunophenotype.

Intravascular lymphoma (IVL) is a rare entity. Most cases are a variant of extranodal diffuse large B cell lymphoma, and fewer than 10% of the published cases are of T cell origin. Only intravascular B cell lymphoma is recognized as a distinct entity in the most recent World Health Organization (WHO) classification of lymphoproliferative disorders. We describe a case of cutaneous natural killer (NK)/T IVL, with a cytotoxic immunophenotype and Epstein-Barr virus (EBV) positivity. However, our case was immunohistochemically negative not only for T cell receptor (TCR)-ßF1 and TCR-γ (TCR-silent), but also for CD56, making it the first triple-negative NK/T IVL case to be described. We urge recognition of this NK/T cell lineage intravascular lymphoma due to its particular immunophenotypical profile and its unvarying relationship with EBV. Its occurrence should not be considered a coincidence, but rather a key aspect of the pathogenic background of this haematological neoplasm.

[WHO classification and clinical spectrum of cutaneous lymphomas]. / WHO-Klassifikation und klinisches Spektrum der kutanen Lymphome.

BACKGROUND: Cutaneous lymphomas are rare skin cancers with a wide clinical spectrum. OBJECTIVE: To give an overview of the current classification and the clinical spectrum of cutaneous lymphomas. MATERIAL AND METHODS: Analysis and summary of the current literature concerning the different entities of cutaneous lymphomas. RESULTS: A few modifications in the nomenclature of cutaneous lymphoma have been introduced in the revised version of the WHO classification 2016. In the last years new types of lymphomatoid papulosis were described. Moreover, two subgroups of folliculotropic mycosis fungoides are now mentioned. The CD4+ small/medium T­cell lymphoproliferative disorder is no longer classified as an overt lymphoma. As new entities the EBV+ mucocutaneous ulcer, an EBV-associated diffuse large B­cell lymphoma (not otherwise specified) and a primary cutaneous acral CD8+ T­cell (provisional) lymphoma are being considered. CONCLUSION: The classification of cutaneous lymphomas is based on the revised version of the WHO classification (2016). The clinical pathological correlation is an elementary component for correct diagnosis.

Clinical manifestations and pathogenesis of cutaneous lymphomas: current status and future directions.

The primary cutaneous lymphomas are a heterogeneous group of T-, Natural Killer- and B- cell neoplasms with a wide range of clinical and pathological presentations, and with very different prognoses compared to systemic lymphomas. Recent studies have shown that the skin microenvironment, which is composed of various immune cell subsets as well as their spatial distribution and T-cell interactions through different chemokines and cytokines, has an important role in the development and pathogenesis of cutaneous lymphomas and has assisted in the development of novel and more effective immunotherapies. The following review will focus on the major subtypes of primary cutaneous lymphomas, including the clinical and histological patterns, molecular hallmarks, and current and future treatment strategies.

Second Primary Malignancies in CTCL Patients from 1992 to 2011: A SEER-Based, Population-Based Study Evaluating Time from CTCL Diagnosis, Age, Sex, Stage, and CD30+ Subtype.

BACKGROUND: Cutaneous T-cell lymphoma (CTCL) is a diverse group of extranodal non-Hodgkin lymphomas with malignant T lymphocytes localizing in the skin. CTCL can mainly be classified as mycosis fungoides, Sézary syndrome, or primary cutaneous CD30+ lymphoma. Patients with CTCL have an increased risk of developing second primary malignancies. OBJECTIVE: Our objective was to analyze the overall incidence of second primary malignancies in patients with CTCL by age, sex, stage, and the primary cutaneous CD30+ lymphoproliferative subtype of CTCL, as this group has usually been excluded from previous analyses. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database to evaluate CTCL cases diagnosed between 1992 and 2011. We calculated the multiple primary standardized incidence ratio, comparing the observed incidence of second primary malignant neoplasms in the CTCL patient population versus the general population. RESULTS: CTCL is associated with an overall increased risk of cancers. This incidence is greatest within the first year of diagnosis. The risk of secondary Hodgkin disease is greatest in patients aged ≥60 years; the risk of secondary non-Hodgkin lymphoma is greatest in patients aged 20-39. Males demonstrated a significantly increased risk of developing Hodgkin lymphoma, while females showed a significantly increased risk of developing bronchopulmonary malignancy. Overall, secondary malignancy incidence was significantly elevated for stage I and IV CTCL. Patients with CD30+ CTCL had a significantly higher incidence of Hodgkin lymphoma, non-Hodgkin lymphoma, and urinary cancers than the general population. CONCLUSION: Occult secondary malignancies, particularly lymphomas, should be considered in adult CTCL patients, including those with the CD30+ subtype.

FoxP3-positive T cell lymphoma arising in non-HTLV1 carrier: clinicopathological analysis of 11 cases of PTCL-NOS and 2 cases of mycosis fungoides.

AIMS: Forkhead box protein 3-positive (FoxP3(+) ) T cell lymphoma, in the absence of human T cell lymphotrophic virus type 1 (HTLV-1) infection, is rare and its clinicopathological characteristics still remain unclear. The aim of this study was to elucidate its characteristics. METHODS AND RESULTS: We describe here 11 cases of peripheral T cell lymphoma not otherwise specified (PTCL-NOS) and two cases of mycosis fingoides (MF) which were positive for FoxP3. The median age of the 11 PTCL-NOS cases was 65 years (range: 48-80 years), and all the patients were male. Eight patients (80%) showed stages III/IV disease, and six (60%) were categorized as high-intermediate/high-risk groups according to the International Prognostic Index. Two cases of MF were 57- and 59-year-old males. Both cases were categorized as stage IA, according to International Society for Cutaneous Lymphomas/European Organization of Research and Treatment of Cancer (ISCL/EORTC) classification. Immunohistochemically, all the cases were negative for cytotoxic molecule marker, and nine (75%) were αß T cell type. Scattered Epstein-Barr virus (EBV)-infected cells were detected in four cases of PTCL-NOS, implying the reactivation of EBV caused by the immunodeficient status of the patients. CONCLUSIONS: FoxP3(+) PTCL-NOS constitute a minor phenotypical subtype with poor prognosis and EBV reactivation in some. Conversely, two cases of MF showed an indolent clinical course which was different from previously reported cutaneous T cell lymphoma (CTCL) cases.

Linfomas cutáneos primarios: frecuencia de los tipos histológicos en una serie de 500 pacientes / Primary cutaneous lymphomas frequency of histological types in a series of 500 patients

Objetivo: analizar las frecuencias de los tipos histopatológico de Linfomas Cutáneos Primarios (LCP) registrados por un grupo colaborativo multicéntrico (redlinfomacutaneo.org.ar). Metodología: analizamos 500 casos provenientes de 24 centros dermatológicos (públicos y privados) de Argentina y uno de Colombia, reportados entre 2010 y 2015. Se incluyeron únicamente casos histológicamente confirmados y estadificados. La información registrada cumple con la Declaración de Helsinki. Resultados: el 94,2% fueron LCP de células T (LCCT) distribuidos en: Micosis fungoide (MF), 75,4%; Desórdenes Linfoproliferativos CD30+, 5,8%; variantes de MF, 4,6%; Síndrome de Sezary, 2,6%; Linfomas T Periféricos tipo NOS, 1,0%; Linfomas de células T-NK Extranodal tipo nasal, 1,0%; Linfomas CD8+ Epidermotropo Agresivo, 1,0%; Linfomas T Pleomórfico CD4+, 0,2%; Leucemia Linfoma T del Adulto, 0,4%. Los LCP de células B (LCCB) fueron el 5,8% y se distribuyeron en: Linfomas Centrofoliculares, 2.4%; Linfomas Marginales, 1,8%; Linfomas B difusos de Células Grandes tipo pierna, 0,4% y tipo NOS, 1%. Conclusiones: confirmamos el predominio de los LCCT pero con una frecuencia de LCCT superior y de LCCB inferior a las reportadas en series europeas o de EE.UU y similar a las de países asiáticos pudiendo obedecer a un sesgo del grupo aportante que sub-registra los LCCB o a factores etiológicos y/o étnicos. (AU)

Aims: to analize the frequency of histopathological types in Primary Cutaneous Lymphoma (PCL) recorded by a multicenter collaborative group (redlinfomacutaneo.org.ar). Methodology: we analized 500 cases from 24 dermatological centers (public and private) of Argentina and one of Colombia, reported between 2010 and 2015 and only being included histological confirmed and staged cases. Recorded information complies with the Declaration of Helsinki. Results: 94,2% were PCL of T cells (CTCL) distributed as follow: Mycosis Fungoides (MF), 75,4%; CD30+ Lymphoproliferative Disorders, 5,8%; MF variants, 4,6%; Sezary Syndrome, 2,6%; Peripheral T cells Lymphoma unspecified, 1,%; Extranodal NK/T cell Lymphoma nasal type, 1,%; CD8+ aggressive epidermotropic lymphoma 1,0%; CD4+ pleomorphic lymphoma, 0,2%; Adult T-cell leukemia/lymphoma, 0, 4%. The PCL B cell (LCCB) were 5.8% and distributed into: follicle center lymphoma, 2.4%; marginal zone lymphoma, 1,8%; diffuse large B-cell lymphoma, leg type, 0,4% and others type, 1%. Conclusions: we confirmed the prevalence of CTCL but with a higher frequency of CTCL and lower of LCCB to those reported in European or US series and similar to those of Asian countries, may be due to a bias of the contributor who underreport LCCB or to etiological and / or ethnic factors. (AU)

Evaluation, Diagnosis, and Staging of Cutaneous Lymphoma.

Primary cutaneous lymphomas (PCLs) are an extremely heterogeneous group of non-Hodgkin lymphomas that manifest in the skin. Their diagnosis is complex and based on clinical lesion type and evaluation of findings on light microscopic examination, immunohistochemistry and molecular analysis of representative skin biopsies. The evaluation, classification, and staging system is unique for mycosis fungoides (MF) and Sézary syndrome (SS), the most common subtypes of cutaneous T-cell lymphoma (CTCL) versus the other subtypes of Non-MF/Non-SS CTCL and the subtypes of cutaneous B-cell lymphoma (CBCL). Since current treatment is stage-based, it is particularly important that the correct diagnosis and stage be ascertained initially. The purpose of this article is to review the current evaluation, diagnosis, classification, staging, assessment techniques, and response criteria for the various types of both T-cell and B-cell PCLs.

Human T-lymphotropic virus type I proviral loads in patients with adult T-cell leukemia-lymphoma: Comparison between cutaneous type and other subtypes.

Adult T-cell leukemia-lymphoma (ATL), characterized by various clinicopathological features, is divided into four clinical subtypes, namely, acute, lymphoma, chronic and smoldering types, and the treatment strategy differs according to the clinical subtype. The designation cutaneous type ATL has been proposed to describe a peculiar subgroup of smoldering type ATL in which the skin is predominantly affected. However, diagnostic criteria and prognostic factors for cutaneous type ATL remain to be determined. Therefore, we performed a retrospective study to obtain a precise method for subtype classification and to clearly define cutaneous type ATL. A total of 87 ATL patients (acute, n = 31; lymphoma, n = 6; chronic, n = 24; smoldering, n = 26) were enrolled. The human T-lymphotropic virus type I (HTLV-1) proviral load in peripheral blood and the serum soluble interleukin-2 receptor (sIL-2R) level were evaluated with respect to the clinical features of the different types of ATL. The HTLV-1 proviral load was significantly increased in the acute and chronic type and the serum sIL-2R level was increased in the acute and lymphoma type. The HTLV-1 proviral load was significantly lower in cutaneous than other smoldering types of ATL without skin lesions. The clinical findings of cutaneous type ATL were also different from other subtypes. These results indicate that, in combination, determination of the HTLV-1 proviral load and the serum sIL-2R level is useful for distinguishing among the different types of ATL, and strongly suggest that cutaneous type ATL is a distinct clinical entity.