CD30-positive primary cutaneous lymphoproliferative disorders: molecular alterations and targeted therapies

The fifth edition of the WHO classification of mature T cell, NK cell and stroma-derived neoplasms

The fifth edition of the WHO Classification of Haematolymphoid Tumors (WHO-HAEM5) introduces significant advancements in the understanding and diagnosis of mature T cell and NK cell, and stroma-derived neoplasms, and incorporates molecular and genetic data/findings accrued over the past years. The classification has been reorganised using a hierarchical system, employed across the fifth edition of the WHO classification of tumours of all organ systems. This review highlights recent developments, evolving concepts, and key updates since the revised fourth edition (WHO-HAEM4R). It enumerates the minimal/essential criteria necessary for diagnosis and classification, constituting not only the importance of clonality analysis in the workup of certain T cell neoplasms and the detection of infectious agents and specific genetic alterations in a subset of entities but also the applicability of these criteria in resource-constrained settings. 'Stroma-derived neoplasms of lymphoid tissues discussed in this review is a new category introduced in HAEM5 that encompasses mesenchymal tumours occurring exclusively in lymph nodes and spleen and mesenchymal dendritic cell neoplasms previously classified as 'histiocytic/dendritic cell neoplasms'.

Primary Cutaneous CD30-Positive Lymphoproliferative Disorders-Current Therapeutic Approaches with a Focus on Brentuximab Vedotin

One of the most common subgroups of cutaneous T-cell lymphomas is that of primary cutaneous CD30-positive lymphoproliferative disorders. The group includes lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large cell lymphoma (pcALCL), as well as some borderline cases. Recently, significant progress has been made in understanding the genetics and treatment of these disorders. This review article summarises the clinical evidence supporting the current treatment options for these diseases. Recent years have seen the introduction of novel agents into clinical practice; most of these target CD30, such as anti-CD30 monoclonal antibodies and conjugated antibodies (brentuximab vedotin), bispecific antibodies and cellular therapies, particularly anti-CD30 CAR-T cells. This paper briefly reviews the biology of CD30 that makes it a good therapeutic target and describes the anti-CD30 therapies that have emerged to date.

CD30+ lymphoproliferative disorder masquerading as an atypical melanocytic proliferation

Heuristics are cognitive strategies used to facilitate decision-making. They can be helpful tools for expediting pathologic diagnoses, however, they can also affect judgment and lead to biases that guide the pathologist astray. We report the case of a 52-year-old female who presented with two unusual pigmented lesions on the wrist and thigh that clinically and histopathologically resembled an atypical melanocytic proliferation. A biopsy of the thigh revealed a broad proliferation of large, atypical cells forming nests within a heavily pigmented epidermis. The lesion was initially misdiagnosed as melanoma in situ, despite equivocal staining for melanocytic markers, likely due to anchoring and adjustment as well as availability biases, which restricted the differential diagnosis and limited the selection of immunohistochemical stains. It was later discovered through chart review that the patient had a prior history of a cutaneous CD30+ lymphoproliferative disorder, which eventually led to the appropriate diagnosis in this case. Herein, we highlight a rare and unusual presentation of a pigmented epidermotropic CD30+ lymphoproliferative disorder, along with the biases leading to its misdiagnosis and the steps leading to the revelation of the actual diagnosis.

A comparison of the International Consensus and 5th WHO classifications of T-cell lymphomas and histiocytic/dendritic cell tumours

Since the publication in 2017 of the revised 4th Edition of the World Health Organization (WHO) classification of haematolymphoid tumours, here referred to as WHO-HAEM4, significant clinicopathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining the diagnostic criteria of several diseases, upgrading entities previously defined as provisional and identifying new entities. This process has resulted in two recent classification proposals of lymphoid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, focusing on T-cell lymphomas and histiocytic/dendritic cell tumours. Moreover, we update the genetic data of the various pathological entities. The main goal is to provide a tool to facilitate the work of the pathologists, haematologists and researchers involved in the diagnosis and treatment of these haematological malignancies.

Primary Cutaneous Anaplastic Large Cell Lymphoma-A Review of Clinical, Morphological, Immunohistochemical, and Molecular Features

Primary cutaneous anaplastic large cell lymphoma (ALCL) is the second most common cutaneous T-cell lymphoma after mycosis fungoides and belongs to the spectrum of cutaneous CD30+ T-cell lymphoproliferative disorders. Although primary cutaneous ALCL usually presents as a localized nodule or papule with or without ulceration, multifocal lesions may occur in up to 20% of cases. Histologically, primary cutaneous ALCL consists of a diffuse dermal infiltrate of medium to large anaplastic/pleomorphic cells with abundant amphophilic-to-eosinophilic cytoplasm, horseshoe-shaped nuclei, strong and diffuse expression of CD30, and with focal or no epidermotropism. The neoplastic infiltrate may show angiocentric distribution and may extend to the subcutis. Patients with localized or multifocal disease have a similar prognosis with a 10-year overall survival rate of 90%. Approximately 30% of primary cutaneous ALCLs harbor a DUSP22 (6p25.3) gene rearrangement that results in decreased expression of this dual-specific phosphatase, decreased STAT3 activation, and decreased activity of immune and autoimmune-mediated mechanisms regulated by T-cells.

Recent advances in cutaneous lymphoma-implications for current and future classifications

The Revised European-American Classification of mature lymphoid neoplasms published in 1994 and the 2001, 2008 and 2016 WHO classifications that followed, were the product of international collaboration and consensus amongst haematopathologists, geneticists, molecular scientists and clinicians. Primary cutaneous lymphomas were fully incorporated into this process following the publication of the WHO-EORTC classification of cutaneous lymphomas in 2005. The definition, diagnostic criteria and recommended studies for primary cutaneous lymphoma continue to be refined. The 2022 International Consensus Classification represents the most recent update and an overview of all the main entities presenting primarily in the skin, together with the major changes in classification, are summarized herein. Primary cutaneous marginal zone lymphoma is segregated from other extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma) and downgraded to a lymphoproliferative disorder in line with its markedly indolent behaviour. In addition, two subtypes are recognised, based largely but not exclusively on whether they are heavy chain class-switched or IgM positive. Similarly, in keeping with a trend to greater conservatism, primary cutaneous acral CD8 positive T cell lymphoma is now also classified as a lymphoproliferative disorder. In addition, significant new insights into the biology of primary cutaneous lymphoma have also recently been forthcoming and will be presented. These studies have enhanced our knowledge of genetic, epigenetic and transcriptional changes in this group of diseases. They not only identify potential targets for novel therapies, but also raise as yet unanswered questions as to how we categorise cutaneous lymphomas, particularly with respect to relationships with similar lymphomas at extracutaneous sites.

Brentuxinmab vedotin, alone or combine with bendamustine in the treatment of natural killer T cell lymphoma

Natural killer (NK)/T cell lymphoma is a highly aggressive subtype of non-Hodgkin lymphoma. The prognosis of patients with natural killer T cell lymphoma (NKTCL) remains poor. More potent treatment strategies are urgently needed to improve the survival of these patients with R/R NKTCL. CD30 expression has been reported to occur in about 40% of NK/T cell lymphoma. Brentuximab vedotin (BV), a monomethyl auristatin E conjugated CD30 antibody, targets CD30 to kill cancer cells. Therapeutic combination of BV and bendamustine has been shown to be highly effective in Hodgkin lymphoma. We investigated efficacy of BV in treating NKTCL as a single therapy, and in combination with bendamustine in vitro and in vivo. We determined CD30 expression levels in 6 NKTCL cell lines. The efficiency of lymphoma cell inhibition by BV correlates with CD30 expression. We also determined the efficacy of BV in combination with bendamustine and found synergistic effects with bendamustine in NKTCL. Combined BV and bendamustine treatment exerted synergistic antiproliferation effect and enhanced cell apoptotic in vitro and in vivo. Brentuximab vedotin and bendamustine synergistically arrested cell cycle at the G2/M phase in NKTCL cell lines. The combination of BV and bendamustine was demonstrated to synergistically damage DNA in NKTCL. This study provides a reference for possible application on using BV for the treatment of NKTCL, either as a single agent or in combination with bendamustine.

Advances in the understanding and treatment of Cutaneous T-cell Lymphoma

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of non-Hodgkin's lymphomas (NHL) characterised by the clonal proliferation of malignant, skin homing T-cells. Recent advances have been made in understanding the molecular pathogenesis of CTCL. Multiple deep sequencing studies have revealed a complex genomic landscape with large numbers of novel single nucleotide variants (SNVs) and copy number variations (CNVs). Commonly perturbed genes include those involved in T-cell receptor signalling, T-cell proliferation, differentiation and survival, epigenetic regulators as well as genes involved in genome maintenance and DNA repair. In addition, studies in CTCL have identified a dominant UV mutational signature in contrast to systemic T-cell lymphomas and this likely contributes to the high tumour mutational burden. As current treatment options for advanced stages of CTCL are associated with short-lived responses, targeting these deregulated pathways could provide novel therapeutic approaches for patients. In this review article we summarise the key pathways disrupted in CTCL and discuss the potential therapeutic implications of these findings.

Genetics Abnormalities with Clinical Impact in Primary Cutaneous Lymphomas

Simple Summary

The genetic landscape of cutaneous T-cell lymphomas analyzed by sequencing high throughput techniques shows a heterogeneous somatic mutational profile and genomic copy number variations in the TCR signaling effectors, the NF-κB elements, DNA damage/repair elements, JAK/STAT pathway elements and epigenetic modifiers. A mutational and genomic stratification of these patients provides new opportunities for the development or repurposing of (personalized) therapeutic strategies. The genetic heterogeneity in cutaneous B-cell lymphoma parallels with the specific subtype. Damaging mutations in primary cutaneous diffuse large B-cell lymphoma of the leg type, involving MYD88 gene, or BCL6 and MYC translocations or CDKN2A deletions are useful for diagnostic purposes. The more indolent forms, as the primary cutaneous lymphoma of follicle center cell (somatic mutations in TNFRSF14 and 1p36 deletions) and the cutaneous lymphoproliferative disorder of the marginal zone cells (FAS gene), present with a more restricted pattern of genetic alterations.

Abstract

Primary cutaneous lymphomas comprise a heterogeneous group of extranodal non-Hodgkin lymphomas (NHL) that arise from skin resident lymphoid cells and are manifested by specific lymphomatous cutaneous lesions with no evidence of extracutaneous disease at the time of diagnosis. They may originate from mature T-lymphocytes (70% of all cases), mature B-lymphocytes (25–30%) or, rarely, NK cells. Cutaneous T-cell lymphomas (CTCL) comprise a heterogeneous group of T-cell malignancies including Mycosis Fungoides (MF) the most frequent subtype, accounting for approximately half of CTCL, and Sézary syndrome (SS), which is an erythrodermic and leukemic subtype characterized by significant blood involvement. The mutational landscape of MF and SS by NGS include recurrent genomic alterations in the TCR signaling effectors (i.e., PLCG1), the NF-κB elements (i.e., CARD11), DNA damage/repair elements (TP53 or ATM), JAK/STAT pathway elements or epigenetic modifiers (DNMT3). Genomic copy number variations appeared to be more prevalent than somatic mutations. Other CTCL subtypes such as primary cutaneous anaplastic large cell lymphoma also harbor genetic alterations of the JAK/STAT pathway in up to 50% of cases. Recently, primary cutaneous aggressive epidermotropic T-cell lymphoma, a rare fatal subtype, was found to contain a specific profile of JAK2 rearrangements. Other aggressive cytotoxic CTCL (primary cutaneous γδ T-cell lymphomas) also show genetic alterations in the JAK/STAT pathway in a large proportion of patients. Thus, CTCL patients have a heterogeneous genetic/transcriptional and epigenetic background, and there is no uniform treatment for these patients. In this scenario, a pathway-based personalized management is required. Cutaneous B-cell lymphoma (CBCL) subtypes present a variable genetic profile. The genetic heterogeneity parallels the multiple types of specialized B-cells and their specific tissue distribution. Particularly, many recurrent hotspot and damaging mutations in primary cutaneous diffuse large B-cell lymphoma of the leg type, involving MYD88 gene, or BCL6 and MYC translocations and BLIMP1 or CDKN2A deletions are useful for diagnostic and prognostic purposes for this aggressive subtype from other indolent CBCL forms.

Anaplastic Large Cell Lymphoma: Molecular Pathogenesis and Treatment

Simple Summary

Anaplastic large cell lymphoma is a rare type of disease that occurs throughout the world and has four subtypes. A summary and comparison of these subtypes can assist with advancing our knowledge of the mechanism and treatment of ALCL, which is helpful in making progress in this field.

Abstract

Anaplastic large cell lymphoma (ALCL) is an uncommon type of non-Hodgkin’s lymphoma (NHL), as well as one of the subtypes of T cell lymphoma, accounting for 1 to 3% of non-Hodgkin’s lymphomas and around 15% of T cell lymphomas. In 2016, the World Health Organization (WHO) classified anaplastic large cell lymphoma into four categories: ALK-positive ALCL (ALK+ALCL), ALK-negative ALCL (ALK−ALCL), primary cutaneous ALCL (pcALCL), and breast-implant-associated ALCL (BIA-ALCL), respectively. Clinical symptoms, gene changes, prognoses, and therapy differ among the four types. Large lymphoid cells with copious cytoplasm and pleomorphic characteristics with horseshoe-shaped or reniform nuclei, for example, are found in both ALK+ and ALK−ALCL. However, their epidemiology and pathogenetic origins are distinct. BIA-ALCL is currently recognized as a new provisional entity, which is a noninvasive disease with favorable results. In this review, we focus on molecular pathogenesis and management of anaplastic large cell lymphoma.

Aggressive Primary Cutaneous Anaplastic T-Cell Lymphoma Successfully Treated with Autologous Stem Cell Transplant and Brentuximab Vedotin Consolidation: Case Report and Review of the Literature

Primary cutaneous CD30+ lymphoproliferative disorders include primary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis. The prognosis of the disease is usually excellent but, in a minority of cases, it presents with extracutaneous involvement and aggressive behavior. The case we present—relapsed after surgical excision, immunosuppressive therapy, and conventional chemotherapy—is the first one treated with Autologous Stem Cell transplant followed by Brentuximab Vedotin consolidation, a scheme already used for high risk Hodgkin Lymphoma.

Functional characterization of NPM1-TYK2 fusion oncogene

Gene fusions are known to drive many human cancers. Therefore, the functional characterization of newly discovered fusions is critical to understanding the oncobiology of these tumors and to enable therapeutic development. NPM1–TYK2 is a novel fusion identified in CD30 + lymphoproliferative disorders, and here we present the functional evaluation of this fusion gene as an oncogene. The chimeric protein consists of the amino-terminus of nucleophosmin 1 (NPM1) and the carboxyl-terminus of tyrosine kinase 2 (TYK2), including the kinase domain. Using in vitro lymphoid cell transformation assays and in vivo tumorigenic xenograft models we present direct evidence that the fusion gene is an oncogene. NPM1 fusion partner provides the critical homodimerization needed for the fusion kinase constitutive activation and downstream signaling that are responsible for cell transformation. As a result, our studies identify NPM1–TYK2 as a novel fusion oncogene and suggest that inhibition of fusion homodimerization could be a precision therapeutic approach in cutaneous T-cell lymphoma patients expressing this chimera.

SOHO State of the Art Updates and Next Questions: Pathology and Pathogenesis of Nodal Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous and often clinically aggressive group of neoplasms derived from mature post-thymic T-lymphocytes. These neoplasms are rare and usually diagnostically challenging. Our understanding of the pathogenesis of PTCL is increasing and this improved knowledge is leading us to better molecular characterization, more objective and accurate diagnostic criteria, more effective risk assessment, and potentially better treatments. The focus of this paper is to present a brief overview of the current pathology criteria and molecular and genetic features of nodal peripheral T-cell lymphomas focusing on distinct genetically and molecularly defined subgroups that are being recognized within each major nodal PTCL category. It is expected that the molecular stratification will improve the diagnosis and will provide novel therapeutic opportunities (biomarker-driven and targeted therapies) that might benefit and change the outcomes of patients with these neoplasms.

Case Report: Contrasting BCL2 Upregulation With Venetoclax in a Case of Refractory Lymphomatoid Papulosis and Progressive Chronic Lymphocytic Leukemia

A 57-year-old man affected by high-risk progressive chronic lymphocytic leukemia (CLL), primary resistant to first-line chemoimmunotherapy, developed a type A lymphomatoid papulosis (LyP) during a second progression of CLL. The two blood tumor entities were clonally unrelated. LyP presented with a diffuse (>90% body surface area) cutaneous rash and was characterized by intensely pruriginous dusky nodules (n = 10) and red flat-topped papules (n = 60). No response to topical corticosteroids and psoralen plus ultraviolet A (PUVA) phototherapy was observed. In order to effectively treat progressive TP53-mutated CLL, the potent BCL2 inhibitor, venetoclax, was initiated with no treatment-related complications. While CLL only achieved a partial response, a complete remission of LyP-associated cutaneous rash and of the intractable pruritus was obtained within 2 months from venetoclax initiation. BCL2 immunostaining of the original cutaneous specimen showed a strong over-expression of the anti-apoptotic protein, restricted to CD30⁺ lymphoid cells and reactive microenvironment. At 12 months follow-up, the patient is still in complete remission of LyP. Our findings underline the probable pathogenic role of BCL2 in LyP and the potential therapeutic efficacy of venetoclax for the treatment of this primary cutaneous CD30⁺ lymphoproliferative disorder, especially in the setting of severe and refractory disease.

Genetic and epigenetic insights into cutaneous T-cell lymphoma

Primary cutaneous T-cell lymphomas (CTCL) constitute a heterogeneous group of non-Hodgkin T-cell lymphomas that present in the skin. In recent years significant progress has been made in the understanding of the pathogenesis of CTCL. Progress in CTCL classifications combined with technical advances, in particular next generation sequencing (NGS), enabled a more detailed analysis of the genetic and epigenetic landscape and transcriptional changes in clearly defined diagnostic entities. These studies not only demonstrated extensive heterogeneity between different CTCL subtypes but also identified recurrent alterations that are highly characteristic for diagnostic subgroups of CTCL. The identified alterations in particular involve epigenetic remodelling, cell cycle regulation, and the constitutive activation of targetable, oncogenic pathways. In this respect, aberrant JAK-STAT signaling is a recurrent theme, however not universal for all CTCL and with seemingly different underlaying causes in different entities. A number of the mutated genes identified are potentially actionable targets for the development of novel therapeutic strategies. Moreover, these studies have produced an enormous amount of information that will be critically important for the further development of improved diagnostic and prognostic biomarkers that can assist in the clinical management of CTCL patients. In the present review the main findings of these studies in relation to their functional impact on the malignant transformation process are discussed for different subtypes of CTCL.

ALK-Negative Anaplastic Large Cell Lymphoma: Current Concepts and Molecular Pathogenesis of a Heterogeneous Group of Large T-Cell Lymphomas

Simple Summary

ALK- anaplastic large cell lymphoma (ALK- ALCL) is a rare subtype of CD30+ large T-cell lymphoma that typically affects older adults and has a poor prognosis. Recognition of its histopathologic spectrum, subtypes, and of other tumors that can resemble ALK- ALCL is crucial to avoid making a wrong diagnosis that could result in inappropriate treatment for a patient. In recent years, several important studies have identified recurrent molecular alterations that have shed light on the pathogenesis of this lymphoma. However, on the other hand, putting all this vast information together into a concise form has become challenging. In this review, we present not only a more detailed view of the histopathologic findings of ALK- ALCL but also, we attempt to provide a more simplified perspective of the relevant genetic and molecular alterations of this type of lymphoma, that in our opinion, is not available to date.

Abstract

Anaplastic large cell lymphoma (ALCL) is a subtype of CD30+ large T-cell lymphoma (TCL) that comprises ~2% of all adult non-Hodgkin lymphomas. Based on the presence/absence of the rearrangement and expression of anaplastic lymphoma kinase (ALK), ALCL is divided into ALK+ and ALK-, and both differ clinically and prognostically. This review focuses on the historical points, clinical features, histopathology, differential diagnosis, and relevant cytogenetic and molecular alterations of ALK- ALCL and its subtypes: systemic, primary cutaneous (pc-ALCL), and breast implant-associated (BIA-ALCL). Recent studies have identified recurrent genetic alterations in this TCL. In systemic ALK- ALCL, rearrangements in DUSP22 and TP63 are detected in 30% and 8% of cases, respectively, while the remaining cases are negative for these rearrangements. A similar distribution of these rearrangements is seen in pc-ALCL, whereas none have been detected in BIA-ALCL. Additionally, systemic ALK- ALCL—apart from DUSP22-rearranged cases—harbors JAK1 and/or STAT3 mutations that result in the activation of the JAK/STAT signaling pathway. The JAK1/3 and STAT3 mutations have also been identified in BIA-ALCL but not in pc-ALCL. Although the pathogenesis of these alterations is not fully understood, most of them have prognostic value and open the door to the use of potential targeted therapies for this subtype of TCL.

Cutaneous T cell lymphoma

Primary cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. CTCL subtypes demonstrate a variety of clinical, histological, and molecular features, and can follow an indolent or a very aggressive course. The underlying pathogenetic mechanisms are not yet entirely understood. The pathophysiology of CTCL is complex and a single initiating factor has not yet been identified. Diagnosis is based on clinicopathological correlation and requires an interdisciplinary team. Treatment decision is made based on short-term and long-term goals. Therapy options comprise skin-directed therapies, such as topical steroids or phototherapy, and systemic therapies, such as monoclonal antibodies or chemotherapy. So far, the only curative treatment approach is allogeneic haematopoietic stem cell transplantation. Novel therapies, such as chimeric antigen receptor T cells, monoclonal antibodies or small molecules, are being investigated in clinical trials. Patients with CTCL have reduced quality of life and a lack of effective treatment options. Further research is needed to better identify the underlying mechanisms of CTCL development and course as well as to better tailor treatment strategies to individual patients.

Cytokines, Genetic Lesions and Signaling Pathways in Anaplastic Large Cell Lymphomas

ALCL is a tumor of activated T cells and possibly innate lymphoid cells with several subtypes according to clinical presentation and genetic lesions. On one hand, the expression of transcription factors and cytokine receptors triggers signaling pathways. On the other hand, ALCL tumor cells also produce many proteins including chemokines, cytokines and growth factors that affect patient symptoms. Examples are accumulation of granulocytes stimulated by IL-8, IL-17, IL-9 and IL-13; epidermal hyperplasia and psoriasis-like skin lesions due to IL-22; and fever and weight loss in response to IL-6 and IFN-γ. In this review, we focus on the biology of the main ALCL subtypes as the identification of signaling pathways and ALCL-derived cytokines offers opportunities for targeted therapies.

Lymphomatoid Papulosis With a Unique T Follicular Helper-Like Phenotype

Lymphomatoid papulosis (LyP) is a benign skin condition that typically presents with grouped or scattered lesions on the body that self-resolve within weeks or months of onset. LyP belongs to the group of CD30-positive lymphoproliferative disorders. Several histological variants of LyP exist, and the histological features of LyP can overlap with other lymphoproliferative disorders; therefore, both histological and clinical correlations are needed for a proper diagnosis of LyP. We report an unusual case of LyP displaying a T follicular helper cell-like phenotype and histopathologically resembling the primary cutaneous CD4-positive small-sized to medium-sized T-cell lymphoproliferative disorder.

Remission of refractory granulomatous primary cutaneous anaplastic large cell lymphoma to brentuximab vedotin

Primary cutaneous anaplastic large cell lymphoma (PC-ALCL) is a rare non-Hodgkin's lymphoma that arises as a single, or multiple dome-shaped tumours on the skin. The histology is characterised by the presence of atypical lymphocytes with large irregularly shaped nuclei that express the surface marker CD30. There can be significant heterogeneity in clinical manifestation and histological pattern and in rare cases accurate diagnosis can be a challenge. Here, we present an unusual case presentation of cutaneous CD30+ anaplastic large cell lymphoma with significant granulomatous histology pattern that mimicked sarcoid. After a lack of durable response to treatments that included glucocorticoid and methotrexate, targeted treatment with anti-CD30 monoclonal antibody drug conjugate (brentuximab vedotin) yielded long-term clinical remission.

Cutaneous T-cell lymphomas-An update 2021

Cutaneous T-cell lymphomas (CTCL) represent the majority of primary cutaneous lymphomas (CL). Mycosis fungoides (MF) and cutaneous CD30+ lymphoproliferative disorders account for 80% of all CTCL. CTCL show overlapping histological features. Thus clinical-pathological correlation is of importance to achieve final diagnosis. MF shows a characteristic evolution with patches, plaques, and in a subset of patients (10%-20%) with tumors. Therapy is stage-adapted with skin-directed therapies such as UV-light therapies and corticosteroids in early disease stage (i.e., patch and limited plaque stage) and systemic therapies (retinoids, interferon, mono chemotherapy, targeted therapy) and/or radiation therapy (local or total skin beam electron) in advanced stages. Novel therapies include targeted therapy such as mogamulizumab (anti-CCR4) or brentuximab vedotin (anti-CD30) and histone deacetylase inhibitors. Considering the impact of targeted therapies, biomarkers such as CD30 are not only crucial for the diagnosis and correct classification of an individual lymphoma case, but also for therapy as they may represent therapeutic targets. In the recently revised WHO classification 2017 and the updated WHO-EORTC classification for CL 2018, primary cutaneous CD8+ acral T-cell lymphoma has been introduced as a new still provisional entity. It displays characteristic clinical, histological, and phenotypic features and exhibits an excellent prognosis. Rare, but aggressive CTCL include cutaneous primary cutaneous aggressive epidermotropic CD8-positive T-cell lymphoma and cutaneous gamma/delta T-cell lymphoma, which present with rapid onset of necrotic or ulcerated plaques and tumors. As they have a poor prognosis, treatment includes multiagent chemotherapy and hematopoietic stem cell transplantation.

How I Diagnose Anaplastic Large Cell Lymphoma

OBJECTIVES

This review describes our approach to the diagnosis of all 4 anaplastic large cell lymphoma (ALCL) entities.

METHODS

ALCLs are a group of CD30-positive mature T-cell lymphomas with similar morphologic and phenotypic characteristics but variable clinical and genetic features. They include systemic ALK-positive ALCL, systemic ALK-negative ALCL, primary cutaneous ALCL, and the recently described provisional entity breast implant-associated ALCL.

RESULTS

In cases with classic features, the diagnosis of ALCL is often straightforward. However, variant histology, the importance of clinical history, and multiple antigenic aberrancies all present challenges to accurate diagnosis and subclassification.

CONCLUSIONS

A systematic approach to the diagnosis of ALCL and awareness of potential mimics are critical to avoid misdiagnosis. It is also crucial to correctly identify localized forms of ALCL to avoid classification as systemic ALCL and subsequent overtreatment.

AP-1 family transcription factors: a diverse family of proteins that regulate varied cellular activities in classical hodgkin lymphoma and ALK+ ALCL

Classical Hodgkin lymphoma (cHL) and anaplastic lymphoma kinase-positive, anaplastic large cell lymphoma (ALK+ ALCL) are B and T cell lymphomas respectively, which express the tumour necrosis factor receptor superfamily member, CD30. Another feature shared by cHL and ALK+ ALCL is the aberrant expression of multiple members of the activator protein-1 (AP-1) family of transcription factors which includes proteins of the Jun, Fos, ATF, and Maf subfamilies. In this review, we highlight the varied roles these proteins play in the pathobiology of these lymphomas including promoting proliferation, suppressing apoptosis, and evading the host immune response. In addition, we discuss factors contributing to the elevated expression of these transcription factors in cHL and ALK+ ALCL. Finally, we examine therapeutic strategies for these lymphomas that exploit AP-1 transcriptional targets or the signalling pathways they regulate.

The expressions of MUM-1 and Bcl-6 in ALK-negative systemic anaplastic large cell lymphoma with skin involvement and primary cutaneous anaplastic large cell lymphoma

BACKGROUND

It is important to differentiate between primary cutaneous anaplastic large cell lymphoma (PC-ALCL) and ALK-negative systemic ALCL with skin involvement, as the prognoses and treatments for these two diseases are considerably different.

OBJECTIVE

This study aimed to compare the expressions of multiple myeloma oncogene 1 (MUM-1) and B-cell lymphoma 6 (Bcl-6) in PC-ALCL and ALK-negative systemic ALCL.

METHODS

This retrospective qualitative study investigated the clinical features of 7 patients with ALK-negative PC-ALCL, 5 patients with ALK-negative systemic ALCL with skin involvement, and 6 patients with ALK-positive systemic ALCL with skin involvement. The MUM-1 and Bcl-6 expressions were evaluated using immunohistochemistry.

RESULTS

The MUM-1 expression rates were 85.7% in the PC-ALCL cases and 100% in the ALK-negative systemic ALCL with skin involvement cases. The Bcl-6 expression rates were 28.5% in the PC-ALCL cases and 20% in the ALK-negative systemic ALCL cases with skin involvement.

CONCLUSION

Although the cutaneous manifestations of ALK-negative systemic ALCL and PC-ALCL are similar, the prognoses and treatment approaches are considerably different. Our results indicate that MUM-1 expression is commonly expressed in both types of ALCL, but Bcl-6 is less commonly expressed in PC-ALCL cases and systemic ALCL with skin involvement cases.

Lymphomatoid papulosis

Lymphomatoid papulosis (LyP) is a non-aggressive skin disorder characterized by papulonodular injuries, sometimes necrotic, often scattered, relapsing, which frequently regress spontaneously. LyP represents about 12% of cutaneous lymphomas. The etiology of LyP is unknown. Based on its histopathology, in 2018, the World Health Organization (WHO) classified LyP into six types with similar prognosis (A,B,C,D,E and DUSP22). Once the diagnosis of LyP has been made, having an excellent prognosis, this pathology must be managed mainly with a "watch and wait" strategy. Treatment should be given only in the presence of diffuse, symptomatic lesions with disfiguring evolution, with the aim of reducing time of resolution and preventing recurrences or the formation of new lesions.

Primary Cutaneous Anaplastic Large Cell Lymphoma (pcALCL) in the Elderly and the Importance of Sport Activity Training

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is part of a spectrum of cutaneous CD30+ lymphoproliferative disease that also includes lymphomatoid papulosis. It often occurs in elderly patients, presenting at a median age of 60 years, although it may occur at any age. It is a CD30+ T-cell neoplasm composed of large cells with anaplastic, pleomorphic, or immunoblastic morphology, with exclusively cutaneous onset and localization. The clinical course of pcALCL is predominantly indolent. Most elderly patients with lymphoma tend to have a sedentary lifestyle, which has a negative effect on their quality of life (QoL) and survival. Several studies indicate that exercise has a positive impact on QoL because it reduces peak oxygen consumption, improves physical capacity, increases self-esteem, reduces accumulated stress, and promotes relaxation. Therefore, particularly in indolent lymphomas, it is necessary to indicate a program of physical activity to be practiced systematically. Complete surgical excision and local radiotherapy are the first line gold standard in pcALCL with a solitary lesion.

An Update on Molecular Biology of Cutaneous T Cell Lymphoma

Cutaneous T cell lymphomas represent a heterogenous group of lymphoproliferative disorders defined by clonal proliferation of T cells present in the skin. The latest WHO classification in 2016 and WHO-EORTC classification in 2018 has updated the classification of these entities based on the molecular profile. Research in the field of molecular genetics of CTCL has allowed a better understanding of the biology of these tumors and has helped to identify potential targets for therapy that can be tailored to individual patients. In this review, we discuss the latest developments in the molecular profile of CTCLs including biomarkers for diagnosis, prognosis, and potential therapeutic targets. We have also touched upon the utility of various molecular diagnostic modalities. For the purpose of this review, we researched papers in PubMed indexed journals in English literature published in the past 20 years using keywords CTCL, mycosis fungoides, molecular profile, molecular diagnosis, whole genome profile, genomic landscape, TCR clonality.

Approach to nodal-based T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of uncommon malignancies derived from mature T cells and usually characterised by an aggressive clinical course. Their clinical presentation, localisation and pattern of dissemination are highly variable, but the majority of cases present as nodal diseases. The recently revised classification of lymphomas has incorporated many new molecular genetic data derived from gene expression profiling and next generation sequencing studies, which refine the definition and diagnostic criteria of several entities. Nevertheless, the distinction of PTCL from various reactive conditions, and the diagnosis of PTCL subtypes remains notably challenging. Here, an updated summary of the clinicopathological and molecular features of the most common nodal-based PTCLs (angioimmunoblastic T-cell lymphoma and other nodal lymphomas derived from follicular T helper cells, anaplastic large cell lymphomas and peripheral T-cell lymphoma, not otherwise specified) is presented. Practical recommendations in the diagnostic approach to nodal T-cell lymphoproliferations are presented, including indications for the appropriate use and interpretation of ancillary studies. Finally, we discuss commonly encountered diagnostic problems, including pitfalls and mimics in the differential diagnosis with various reactive conditions, and the criteria that allow proper identification of distinct PTCL entities.

Prognostic factors in patients with primary cutaneous anaplastic large cell lymphoma: a multicentric, retrospective analysis of the Spanish Group of Cutaneous Lymphoma

BACKGROUND

Reliable prognostic factors for patients with primary cutaneous anaplastic large cell lymphoma (PCALCL) are lacking.

OBJECTIVE

To identify prognostic factors for specific survival in patients with PCALCL.

METHODS

Using the convenience sampling method, patients with PCALCL diagnosed from May 1986 to August 2017 in 16 University Departments were retrospectively reviewed.

RESULTS

One hundred eight patients were included (57 males). Median age at diagnosis was 58 years. All of them showed T1-3N0M0 stages. Seventy per cent of the cases presented with a solitary lesion, mostly at the limbs. Complete response rate after first-line treatment was 87%, and no advantage was observed for any of them (surgery, radiotherapy, chemotherapy or other approaches). Nodal and visceral progression rate was 11% and 2%, respectively. 5-year specific survival (SSV) reached 93%; 97% for T1 patients and 84% for T2/T3 patients (P = 0.031). Five-year SSV for patients developing early cutaneous relapse was 64%; for those with late or no relapse, 96% (P = 0.001). Estimated median SSV for patients showing nodal progression was 103 months (95% CI: 51-155 months); for patients without nodal progression, estimated SSV did not reach the median (P < 0.001). Nodal progression was an independent predictive parameter for shorter survival (P = 0.011).

CONCLUSION

Multiple cutaneous lesions at presentation, early skin relapse and nodal progression portrait worse prognosis in patients with PCALCL.

How I treat primary cutaneous CD30+ lymphoproliferative disorders

The primary cutaneous CD30+ lymphoproliferative disorders are a family of extranodal lymphoid neoplasms that arise from mature postthymic T cells and localize to the skin. Current classification systems recognize lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma, and borderline cases. In the majority of patients, the prognosis of primary cutaneous CD30+ lymphoproliferative disorders is excellent; however, relapses are common, and complete cures are rare. Skin-directed and systemic therapies are used as monotherapy or in combination to achieve the best disease control and minimize overall toxicity. We discuss 3 distinct presentations of primary cutaneous CD30+ lymphoproliferative disorder and present recommendations for a multidisciplinary team approach to diagnosis, evaluation, and management of these conditions in keeping with existing consensus guidelines.