The Grey Zones of Classic Hodgkin Lymphoma

A proteome-wide analysis unveils a core Epstein-Barr virus antibody signature of classic Hodgkin lymphoma across ethnically diverse populations

Epstein-Barr virus (EBV) is an oncogenic virus associated with various malignancies, including classical Hodgkin lymphoma (cHL). Despite its known association, the specific role of humoral immune response to EBV remains poorly characterized in cHL. To address this, we conducted a study using a custom protein microarray to measure the antibody responses in cHL patients and matched healthy controls recruited from an East-Asian hospital-based case-control study. We identified 16 IgG antibodies significantly elevated in EBV-positive cHL compared with controls, defining an "East-Asian antibody signature of EBV-positive cHL." We evaluated responses against these 16 antibodies in a distinct European population, leveraging data from our previous European cHL case-control study from the UK, Denmark, and Sweden. A subset of antibodies (14/16, 87.5%) from the "East-Asian antibody signature of EBV-positive cHL" exhibited significant associations with cHL in the European population. Conversely, we assessed the "European antibody signature of EBV-positive cHL" identified in our prior study which consisted of 18 EBV antibodies (2 IgA, 16 IgG), in the East-Asian population. A subset of these antibodies (15/18, 83.3%) maintained significant associations with cHL in the East-Asian population. This cross-comparison of antibody signatures underscores the robust generalizability of EBV antibodies across populations. Five anti-EBV IgG antibodies (LMP-1, TK, BALF2, BDLF3, and BBLF1), found in both population-specific antibody signatures, represent a "core signature of EBV-positive cHL." Our findings suggest that the antibody responses targeting these core EBV proteins reflect a specific EBV gene expression pattern, serving as potential biomarkers for EBV-positive cHL independent of population-specific factors.

Initial Diagnosis of Classic Hodgkin Lymphoma With Skin Biopsy: A Rare Case and Review of Diagnostic Considerations

ABSTRACT

Classic Hodgkin lymphoma (CHL) is a B-cell-derived lymphoma that classically displays a bimodal age distribution. CHL typically involves the mediastinum, lymph nodes, and other visceral organs. CHL is characterized histologically by the presence of a relatively paucicellular neoplastic cell population composed of large atypical cells (including Hodgkin and Reed-Sternberg forms) in a reactive mixed inflammatory background, often with prominent necrosis. CHL rarely occurs in the skin, and the associated mixed inflammatory infiltrate or necrotic appearance can create diagnostic uncertainty. Herein, we report the case of a 31-year-old man presenting with a painful dendritic rash of the anterior chest wall with axillary lymphadenopathy. After multiple nondiagnostic biopsies that revealed largely necrotic material, a chest wall skin biopsy was obtained. The skin biopsy was diagnostic of CHL, based on the presence of large atypical dermal cells, including Hodgkin and Reed-Sternberg forms, which expressed CD15, CD30 and Fascin, in a typical mixed inflammatory and necrotic background. Through the lens of this case, we discuss the characteristics and mechanisms of skin involvement of CHL, and the histopathologic and immunohistochemical pitfalls when considering the rare diagnosis of CHL in the skin.

Genetic Factors in Familial Manifestation of Primary Mediastinal Large B-Cell Lymphoma over Two Generations

INTRODUCTION

Primary mediastinal large B-cell lymphoma (PMBL) is a rarely occurring lymphoid malignancy which typically affects young adults and presents itself as an anterior mediastinal mass. Gene expression profiling as well as somatic genetic analysis revealed that it is closely related to classical Hodgkin lymphoma, whereas morphologically, it tends to resemble diffuse large B-cell lymphoma. Familial clustering of PMBL is rare - only two reports have been published to date. While it is generally accepted that positive family history is associated with increased risk of developing a lymphoma, genetic risk factors which might predispose to PMBL are largely unknown.

CASE PRESENTATION

We performed germline and tumor genetic analyses by whole-exome sequencing and array-CGH of a family, in which the father and the son both developed a PMBL. Germline investigations of both affected patients and of their two unaffected family members have not been able to provide a single risk factor associated with lymphoma predisposition. In addition, genes that were previously implicated in increased risk for PMBL, namely MLL (KMT2A) and TIRAP, were found to be intact in all investigated family members. Somatic genetic investigations identified known as well as novel genetic aberrations in tumors of the affected subjects.

CONCLUSION

We conclude that predisposition to a PMBL might be inherited through a combination of low- or moderate-risk factors and provide a shortlist of the most likely selected candidates, which can be used in future studies.

Gray zone lymphoma: A case report and comprehensive review of literature

Gray zone lymphoma is a very rare liquid malignancy that possesses intersecting features between primary mediastinal B-cell lymphoma and classic Hodgkin Lymphoma. In the case presented and accompanying literature review, we will discuss a patient with a chief complaint of shortness of breath and was found to have a mediastinal mass with biopsy consistent with mediastinal gray zone lymphoma. Herein, we explore the historical and recently updated diagnostic criteria of gray zone lymphoma from 2022 as well as the pathophysiology as it pertains to gene expression, while also reviewing the histological findings, epidemiology and treatment modalities.

Hodgkin Lymphoma-The Spectrum from Diagnostics to Molecular Science, Movement and Current Treatment Approaches

A total of fourteen papers on Hodgkin lymphoma (HL) are published within this Special Issue, including six reviews, seven original articles and one commentary [...].

Tumor microenvironment contribution to checkpoint blockade therapy: lessons learned from Hodgkin lymphoma

Classic Hodgkin lymphoma (cHL) is characterized by a tumor microenvironment (TME) containing inflammatory/immune cells. Follicular lymphoma, mediastinal gray zone lymphoma, and diffuse large B-cell lymphomas may show a TME containing inflammatory/immune cells, but the TMEs are quite different. In B-cell lymphomas and cHL, programmed cell death 1 (PD-1)-PD ligand 1 pathway blockade drugs differ in their effectiveness among patients with refractory/relapsed disease. Further research should explore innovative assays that could reveal which molecules influence sensitivity or resistance to therapy in an individual patient.

[Classification of Hodgkin lymphoma and related entities : News and open questions]

Two new classifications were recently released: the 5th edition of the WHO classification of hematolymphoid tumors and the International Consensus Classification (ICC) drafted by the Clinical Advisory Committee. In the preparation of both classifications, the previously existing lymphoma categories were reevaluated according to recently obtained data on clinical, morphological, and molecular findings. In this review we summarize the current placements of classic and nodular lymphocyte predominant Hodgkin lymphoma and their relevant differential diagnoses.

Classification of B-Cell Lymphomas and Immunodeficiency-Related Lymphoproliferations: What’s New?

New insights from genomic studies have had an impact on the definition and the diagnosis of several lymphoid tumors including follicular B-cell lymphomas, aggressive diffuse large B-cell lymphomas, and lymphoproliferations associated with acquired and posttransplant immunodeficiencies. Follicular lymphoma (FL) includes tumors whose behavior varies widely from indolent/early lesions to aggressive/transformed lymphomas. Although some large B-cell lymphomas can be subclassified as specific entities, the majority lack the characteristics necessary for subclassification and, thus, are termed diffuse large B-cell lymphoma, NOS. There have been, however, some changes in the classification of specific subtypes of large B-cell lymphoma as well as the addition of new entities, a few of which are highlighted in this article. The immunodeficiency-related lymphoproliferative disorders are currently divided into four major categories based on the clinical setting in which they arose: primary immune deficiency, post-transplant, HIV infection, and iatrogenic immunosuppression. In the two upcoming classifications systems for hematolymphoid neoplasms, International Consensus Classification (ICC) and WHO-HAEM-5, there is a divergence in the approach to categorize these lesions. Furthermore, whereas the WHO-HAEM-5 confirms the ability to classify a spectrum of EBV+ lesions as EBV+ DLBCL, NOS, the ICC has separated out lesions that are composed of a heterogenous cellular infiltrate into a new separate category, “EBV-positive polymorphic B cell lymphoproliferative disorder, NOS”. Both WHO-HAEM-5 and ICC recognize a number of KSHV/HHV8-associated lymphoid lesions and acknowledge that there is significant overlap among the different lesions. In the future, translation of these innovations in general practice requires further validation.

Targeted Mutational Profiling Reveals Clonal Relationships in Metachronous Occurrence of Classic Hodgkin and Mediastinal Large B-Cell Lymphomas

Classic Hodgkin lymphoma (CHL) patients may infrequently present with a prior or recurrent disease with discordant histology resembling non-Hodgkin lymphomas. These include primary mediastinal large B-cell lymphoma (PMBL), diffuse large B-cell lymphoma (DLBCL), or mediastinal gray-zone lymphoma (MGZL). Such patients are often refractory to standard therapy and their diagnosis is hampered by significant morphologic and immunophenotypic overlap and insufficient molecular data. Among 509 CHL patients seen at an academic medical center, 6 patients had a prior or subsequent diagnosis different from CHL. Paired tissue samples were evaluated by targeted mutational analysis using a 164-gene panel. Our findings show multiple shared variants indicative of a clonal relationship between the CHL and the PMBL, DLBCL, or MGZL diagnoses. Most frequent mutated genes included TNFAIP3 (4 of 6, 66.7%), STAT6 (3 or 6, 50%), ARID1A (3 of 6, 50%), and XPO1 (3 of 5, 60%). Three patients showed the same oncogenic variant within the XPO1 gene (E571K), and mutations in TNFAIP3 and B2M were observed in 2 of the 5 patients with shared variants. In addition, differences in the mutation profile between the lymphoma pairs were also observed, which could represent clonal evolution. Mutational profiling could be of benefit in patients with recurrent/refractory disease with discordant histology, where the clonal relationship could be helpful to inform and guide therapeutic decisions. These findings provide further evidence of a true biological continuum surrounding CHL, PMBL, DLBCL, and MGZL and shed light on underlying genetic events and their clinical impact.

Evolution in the definition and diagnosis of the Hodgkin lymphomas and related entities

Hodgkin lymphoma was the first of the lymphomas to be recognized as a specific disease entity. However, recent studies have highlighted the heterogeneity of the diseases associated with this eponym warranting clarification and refinement of diagnostic terminology. While classic Hodgkin lymphoma (CHL) remains an essentially unchanged diagnostic entity in the 2022 International Consensus Classification of Mature Lymphoid Neoplasms (2022 ICC), nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is now renamed nodular lymphocyte predominant B cell lymphoma (NLPBL) in recognition of the distinct pathologic, biologic, and clinical differences. Fan patterns A, B, and C (sharing the presence of evident follicular structures, and retention of a B cell rich background) will be combined in "typical" or grade 1, while the other "variant" patterns, D, E, and F, are considered grade 2. T-cell/histiocyte-rich large B cell lymphoma (THRBCL) is considered part of the "variant" NLPHL continuum.The entity previously known as "B cell lymphoma, unclassifiable (BCLU), with features intermediate between diffuse large B cell lymphoma (DLBCL) and CHL" has been renamed "mediastinal gray zone lymphoma" (MGZL) in recognition of the importance of the thymic niche in the biology of this tumor. The diagnostic criteria for MGZL have been refined and require both a high tumor cell density and a strongly preserved B cell program.This article will describe updates on CHL, NLPBL, and MGZL in the recently published 2022 ICC and provide some useful differential diagnostic clues in cases with atypical morphology or immunophenotype.

A comparison of the International Consensus and 5th World Health Organization classifications of mature B-cell lymphomas

Several editions of the World Health Organization (WHO) classifications of lympho-hemopoietic neoplasms in 2001, 2008 and 2017 served as the international standard for diagnosis. Since the 4th WHO edition, here referred as WHO-HAEM4, significant clinico-pathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, to upgrade entities previously defined as provisional and to identify new entities. This process has resulted in two recent classifying 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, with focus on mature B-cell neoplasms. The main aim is to provide a tool to facilitate the work of pathologists, hematologists and researchers involved in the diagnosis and treatment of lymphomas.