Rare variants in the spectrum of human herpesvirus 8/Epstein-Barr virus–copositive lymphoproliferations

Epstein-Barr virus reactivation influences clonal evolution in human herpesvirus-8-related lymphoproliferative disorders

Background

Human herpesvirus‐8 (HHV8) is a lymphotropic virus associated with different lymphoproliferative disorders, including primary effusion lymphoma (PEL), multicentric Castleman’s disease (MCD), diffuse large B‐cell lymphomas, not otherwise specified, and the rare entity known as germinotropic lymphoproliferative disorder (GLPD). In PELs and GLPD the neoplastic cells also contain Epstein–Barr virus (EBV). In addition, occasional cases with atypical and overlapping features among these entities have been recognised, suggesting that the spectrum of the HHV8‐related lesions may not be fully characterised.

Aims

Here, we report two cases of lymphoproliferative disorder associated with HHV8 and EBV that further expand the spectrum of HHV8/EBV‐positive lymphoproliferative disease.

Methods and results

Case 1 represented HHV8/EBV‐positive extracavitary nodal PEL followed by pleural PEL. The striking characteristic of this case was the almost focal and intrasinusoidal localisation of the neoplastic cells and the association with Castleman’s disease features. In the second case, we found the entire spectrum of HHV8‐related disorders, i.e. MCD, GLPD, and PEL, coexisting in the same lymph node, underlining the variability, possible overlap and evolution among these entities. Both cases were well analysed with immunohistochemistry, determination of the EBV latency programme, and molecular analysis for clonality of immnoglobulin genes. In both patients, the disease followed an unexpected indolent course, both being still alive after 8 and 12 months, respectively.

Conclusion

Our findings represent further evidence of the overlap among HHV8/EBV‐positive lymphoproliferative disorders, and underline a grey zone that requires further study; they further confirm the experimental evidence that lytic EBV replication influences HHV8‐related tumorigenesis.

Human herpes virus 8-positive germinotropic lymphoproliferative disorder: first case diagnosed in the UK, literature review and discussion of treatment options

We present this case of human herpes virus 8-positive germinotropic lymphoproliferative disorder in a 20-year-old woman seen in the surgical oncology clinic for localised lymphadenopathy. This is the first case to be reported in the UK, and we discuss it along with a literature review including investigations and treatment options. This will demonstrate the importance of preoperative workup and multidisciplinary teamwork in deciding management plans and serve as a guide for future encounters of this rare condition in clinical practice.

Human herpesvirus 8-positive multicentric Castleman disease with germinotropic plasmablastic aggregates: Overlapping spectrum of human herpesvirus 8-associated lymphoproliferative disorder

The diagnosis of human herpesvirus 8 (HHV8)-associated lymphoproliferative disorder (LPD) is challenging because of the rarity and extended spectrum of each entity. A 43-year-old, human immunodeficiency virus seropositive, Japanese man was referred to our department because of persistent fever, generalized lymphadenopathy, jaundice and anasarca. Biopsy of a left axially lymph node demonstrated relatively preserved nodal structure with multicentric Castleman disease (MCD) features. In the germinal center, there were aggregates of HHV8-infected plasmablasts that were diffusely positive for CD38, MUM1/IRF4, LCA, IgM and λ; partially positive for CD30, c-MYC, p53; and negative for CD138, CD20, PAX-5, κ, CD2, CD3 and CD5. A small number of Epstein-Barr virus encoded small RNA (EBER)-positive large cells infiltrated in the outer part of the germinal center and the mantle layer, but the cells copositive for EBER and HHV8 were not evident. We diagnosed the patient as HHV8-positive MCD with germinotropic plasmablastic aggregates, which demonstrated intermediate pathologic features between HHV8-positive MCD and germinotropic lymphoproliferative disorder. The pathogenesis of each HHV8-associated LPD differs in cellular origin, host immune status, cytoplasmic immunoglobulin expression, clonality pattern and EBV infection; however, these factors sometimes overlap and induce extended clinical and pathologic presentations.

Intrasinusoidal HHV8-EBV-Positive Large B-Cell Lymphoma With Features of Germinotropic Lymphoproliferative Disorder

Germinotropic lymphoproliferative disorder (GLPD) is a poorly characterized lymphoproliferative entity, recently included in the World Health Organization classification of hematolymphoid neoplasms. The histological pattern of this disease comprises monotypic plasmablasts that involve the germinal centers of the lymphoid follicles (germinotrophism), forming confluent aggregates positive for both human herpes virus type 8 (HHV8) and Epstein-Barr virus. Currently, after 17 years of its first description, only 18 cases have been reported. In this article, we describe a case of a GLPD presenting in an immunocompetent 79-year-old woman with localized axillary lymphadenopathy, showing a prominent sinusoidal growth pattern, with no evidence of germinotrophism or extrasinusoidal spread. Stinking pleomorphism in tumor cells was also noted. An extension study has not revealed involvement of other groups of lymph nodes or extralymphoid sites. The patient is alive and has shown no relapse after 8 years follow-up (the longest follow-up reported period for this entity). This previously unrecognized pure sinusoidal growth pattern along with the striking pleomorphism in neoplastic cells closely mimics the appearance of an anaplastic large cell lymphoma. GLPD is not usually considered in such a setting, but it should be included in the differential diagnosis of sinusoidal proliferations. Our findings contribute to the expansion of the morphological spectrum of HHV8-associated lymphoproliferative lesions and aids in the characterization of the very infrequent GLPD entity.

Germinotropic lymphoproliferative disorder: a systematic review

Germinotropic lymphoproliferative disorder is a rare and rather enigmatic novel entity with distinctive clinicopathological features, one of which is the typical co-infection by Human herpesvirus 8 and Epstein-Barr virus. Human herpesvirus 8 is a lymphotropic virus detected in Kaposi sarcoma, multicentric Castleman disease, primary effusion lymphoma, Human herpesvirus 8-positive diffuse large B cell lymphoma not otherwise specified, and germinotropic lymphoproliferative disorder. Co-infection by Human herpesvirus 8 and Epstein-Barr virus is identified only in two lymphoproliferative diseases: germinotropic lymphoproliferative disorder and primary effusion lymphoma, which are otherwise diseases with totally different clinical presentations and outcomes. Unlike primary effusion lymphoma mostly occurring in immunocompromised individuals and following an aggressive course, germinotropic lymphoproliferative disorder usually presents with single or multiple lymphadenopathy affecting mainly immunocompetent individuals and mostly follows an indolent course. Based on the PRISMA guidelines, we carried out a systematic search on PubMed/MEDLINE, Web of Science, Scopus, EMBASE, and Cochrane Library using the search terms "germinotropic" and "lymphoproliferative disorder." Current scientific literature reports just 19 cases of germinotropic lymphoproliferative disorder. The purpose of our systematic review is to improve our understanding of the disease, focusing on epidemiology, clinical presentation, pathological features, treatment, and outcome. In addition, we discuss the differential diagnosis with the other Human herpesvirus 8-related lymphoproliferative diseases as currently recognized in the World Health Organization classification, adding a focus on lymphoproliferative disorders showing overlapping features.

Epstein-Barr virus-associated B-cell lymphoproliferative disorders and lymphomas: a review

In this review, we focus on B-cell lymphoproliferative disorders (LPDs) and lymphomas associated with Epstein-Barr virus (EBV). In some of these diseases-such as EBV-positive diffuse large B-cell lymphoma (DLBCL), not otherwise specified-virus detection is required for the diagnosis, while in others its detection is not necessary for diagnosis. EBV infection has three main latency patterns (types III, II, and I). Different latency patterns are found in different LPD types and are related to the host immune system status. For each of the LPDs/lymphomas, we discuss the clinical presentation, epidemiology, pathology, immunophenotype, and genetic or molecular basis. We provide data for a better understanding of the relationships among the discussed diseases and other information that can be useful in differential diagnosis. Not included in this review are classic Hodgkin lymphoma and some specific variants of DLBCL, as these entities are discussed in separate reviews in this issue.

[Revised WHO classification of tumors of hematopoietic and lymphoid tissues, 2017 (4th edition):lymphoid tumors]

The paper is devoted to changes in the 4^th edition of the WHO classification of lymphoid tumors in the 2017 revision, to the principles of the structure and features of the classification. It discusses changes in the identification of new clinical and morphological categories and in the abolition of some previously existing ones. New information about lymphoid tumors, their immunophenotypic and molecular characteristics of classification importance are briefly outlined. The absolute need for molecular genetic studies for the diagnosis of certain lymphoproliferative diseases is underlined. The characteristics of lymphoid pretumor states are given.

HHV-8-Associated Lymphoproliferative Disorders and Pathogenesis in an HIV-Positive Patient

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, is a DNA oncovirus known for its role in the development of Kaposi's sarcoma (KS) and several lymphoproliferative disorders (LPDs). HHV-8 promotes lymphoproliferation via the activation of the interleukin-6 receptor signaling pathway, as well as a host of other regulatory mechanisms. The spectrum of HHV-8-associated LPDs is increasing. The World Health Organization has recently updated the classification of HHV-8-associated LPDs by introducing HHV-8-positive germinotropic LPD (GLPD) in addition to the previously recognized entities of HHV-8-positive diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), primary effusion lymphoma (PEL), and HHV-8-positive multicentric Castleman's disease (MCD). We present here a case of an HIV-positive woman with a history of KS, who later developed three HHV-8-associated LPDs, including HHV-8-positive MCD, PEL, and GLPD. To the best of our knowledge, this is the first reported case of a patient with this combination of individually rare HHV-8-associated LPDs. This case illustrates the spectrum and the sequential development of the different clinical manifestations of HHV-8-associated diseases. Detection of HHV-8 can have clinical significance in the diagnosis and management of certain HHV-8-associated conditions. Recently discovered variants of HHV-8-associated LPDs indicate that this group represents a diverse spectrum of disorders, whose classification may require further refinement beyond the currently recognized entities.

Persistent KSHV Infection Increases EBV-Associated Tumor Formation In Vivo via Enhanced EBV Lytic Gene Expression

The human tumor viruses Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) establish persistent infections in B cells. KSHV is linked to primary effusion lymphoma (PEL), and 90% of PELs also contain EBV. Studies on persistent KSHV infection in vivo and the role of EBV co-infection in PEL development have been hampered by the absence of small animal models. We developed mice reconstituted with human immune system components as a model for KSHV infection and find that EBV/KSHV dual infection enhanced KSHV persistence and tumorigenesis. Dual-infected cells displayed a plasma cell-like gene expression pattern similar to PELs. KSHV persisted in EBV-transformed B cells and was associated with lytic EBV gene expression, resulting in increased tumor formation. Evidence of elevated lytic EBV replication was also found in EBV/KSHV dually infected lymphoproliferative disorders in humans. Our data suggest that KSHV augments EBV-associated tumorigenesis via stimulation of lytic EBV replication.

HHV8/EBV Coinfection Lymphoproliferative Disorder: Rare Entity with a Favorable Outcome

HHV8/EBV-associated germinotropic lymphoproliferative disorder (GLD) is a challenging diagnosis given its rarity, the particular clinical presentation, and the lack of expression of markers usually used in establishing hematopoietic lineage. We report a new case of HHV8/EBV GLD in an immunocompetent 78-year-old woman. The diagnosis was made in an incidentally discovered lymphadenopathy. Histological examination showed a nodular lymphoid proliferation centered by aggregates of atypical plasmablastic cells admixed with small lymphoid cells. Tumor cells were strongly positive with EMA, HHV8, LMP1, CD38, CD138, and kappa light chains. They were negative with common lymphoma-associated markers (CD20, CD3, CD15, CD30, CD10, and bcl2). In situ hybridization confirmed the monotypic kappa light chains and the EBV infection (EBER+). A polyclonal pattern of Ig gene rearrangement was detected by PCR analysis. In the adjacent lymph node parenchyma, some germinal centers mimicked Castleman disease. In this case, the differential diagnosis was discussed with an early stage of large B-cell lymphoma arising in HHV8-associated multicentric Castleman disease. The clinical presentation, the immunophenotype, and the molecular results helped to make the accurate diagnosis. Through the review of the nine previously reported cases in literature, we discuss the clinical and pathologic features and the differential diagnosis of HHV8/EBV GLD.

HHV8/KSHV-Positive Lymphoproliferative Disorders and the Spectrum of Plasmablastic and Plasma Cell Neoplasms: 2015 SH/EAHP Workshop Report-Part 3

OBJECTIVES

The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review immunodeficiency-related lymphoproliferative disorders with plasmablastic and plasma cell differentiation.

METHODS

The workshop panel reviewed human herpes virus 8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV)-associated lesions and other lesions exhibiting plasma cell differentiation, including plasmablastic proliferations with features of myeloma/plasmacytoma, plasmablastic neoplasms presenting in extranodal sites and effusion-based lymphomas, and rendered a consensus diagnosis.

RESULTS

The spectrum of HHV8/KSHV-associated proliferations ranged from multicentric Castleman disease (MCD) to MCD with plasmablastic aggregates to HHV8+ diffuse large B-cell lymphoma and germinotrophic lymphoproliferative disorder. Comparisons across effusion-based lymphomas with and without HHV8/KSHV and plasmablastic lymphomas in immunodeficient and immunocompetent patients were discussed.

CONCLUSIONS

The presence or absence of HHV8/KSHV is a defining feature in disorders associated with Castleman disease, although their differential diagnosis and recognition of progression may be challenging. Plasmablastic proliferations overlap with myeloma/plasmacytoma as well as extranodal and effusion-based lymphomas. The involvement of Epstein-Barr virus is typically variable.

Expression patterns of the activator protein-1 (AP-1) family members in lymphoid neoplasms

The activator protein-1 (AP-1) is a dimeric transcription factor composed of proteins belonging to the Jun (c-Jun, JunB and JunD), Fos (c-Fos, FosB, Fra1 and Fra2) and activating transcription factor protein families. AP-1 is involved in various cellular events including differentiation, proliferation, survival and apoptosis. Deregulated expression of AP-1 transcription factors is implicated in the pathogenesis of various lymphomas such as classical Hodgkin lymphomas, anaplastic large cell lymphomas, diffuse large B cell lymphomas and adult T cell leukemia/lymphoma. The main purpose of this review is the analysis of the expression patterns of AP-1 transcription factors in order to gain insight into the histophysiology of lymphoid tissues and the pathology of lymphoid malignancies.

Multicentric Castleman disease: Where are we now?

Multicentric Castleman disease (MCD) encompasses a spectrum of conditions that give rise to overlapping clinicopathological manifestations. The fundamental pathogenetic mechanism involves dysregulated cytokine activity that causes systemic inflammatory symptoms as well as lymphadenopathy. The histological changes in lymph nodes resemble in part the findings originally described in the unicentric forms Castleman disease, both hyaline vascular and plasma cell variants. In MCD caused by Kaposi sarcoma-associated herpesvirus/human herpesvirus-8 (KSHV/HHV8), the cytokine over activity is caused by viral products, which can also lead to atypical lymphoproliferations and potential progression to lymphoma. In cases negative for KSHV/HHV8, so-called idiopathic MCD, the hypercytokinemia can result from various mechanisms, which ultimately lead to different constellations of clinical presentations and varied pathology in lymphoid tissues. In this article, we review the evolving concepts and definitions of the various conditions under the eponym of Castleman disease, and summarize current knowledge regarding the histopathology and pathogenesis of lesions within the MCD spectrum.

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.