Age and CD20 Expression Are Significant Prognostic Factors in Human Herpes Virus-8-negative Effusion-based Lymphoma

Advances in the Classification of Aggressive B-cell Lymphomas

Aggressive B-cell lymphomas are a biologically and clinically very heterogeneous group of tumors that may be related to different stages of B-cell differentiation development. This review aims to summarize recent advances in the understanding of these tumors with a focus on the practical approach to the diagnosis of these entities. We analyze the defining characteristics of the different subtypes of aggressive B-cell lymphomas, including nodal and extranodal diffuse large B-cell lymphoma, virus-associated lymphomas, terminally differentiated B-cell lymphomas, high-grade B-cell lymphomas, and Burkitt lymphoma. This review particularly explores the integration of morphologic, immunophenotypic, and genetic data that refine diagnostic accuracy and prognostic stratification, underscoring the necessity for a standardized approach in clinical practice. By synthesizing current knowledge, this review aims to enhance the understanding of aggressive B-cell lymphomas within the context of the evolving classification system, paving the way for future research and clinical advancements.

Sarcopenia is a prognostic factor in lymphoma patients: a systematic review and meta-analysis

Findings regarding the relationship between sarcopenia and lymphoma have been inconsistent across studies. This study investigated the association between sarcopenia and lymphoma. We systematically searched the Embase, Science Direct, Cochrane Library, and PubMed databases from inception to 31 March 2024 to identify relevant studies. Two researchers independently extracted and evaluated studies that met inclusion and exclusion criteria. Twenty-six studies with 3659 participants were included. Sarcopenic lymphoma patients had poor overall survival (OS) (HR = 1.88; 95% CI: 1.47-2.41; p < 0.001). The heterogeneity was high (I2=80%). However, the result of the Egger test indicated a significant publication bias (p < 0.001). After employing the trim and fill method to adjust for this bias, the HR of OS became non-significant (p > 0.05). The progression-free survival (PFS) was worse in sarcopenic patients (HR = 1.77; 95% CI: 1.37-2.29; p < 0.001; I2=70%). There was no significant publication bias (p > 0.05). In the subgroup analyses, sarcopenia was a negative predictor of OS in lymphoma patients who undergo hematopoietic cell transplantation (HCT) (HR  = 1.61;95% CI: 1.19-2.18; I2=30%). Male lymphoma patients with sarcopenia had a significantly worse OS (HR = 2.29; 95% CI:1.24-4.24; p = 0.009). Among patients with primary central nervous system lymphoma (PCNSL), those with sarcopenia defined by temporal muscle thickness (TMT) exhibited significantly worse OS (HR = 2.20; 95% CI:1.04-4.65; p = 0.039; I2=68%). Sarcopenia is associated with worse PFS in lymphoma patients. Subgroup analyses indicate that sarcopenia is a negative predictor of OS after HCT, and male lymphoma patients who suffer from sarcopenia have higher mortality. Sarcopenia defined by TMT is also a negative predictor of OS for patients with PCNSL.

Update: The molecular spectrum of virus-associated high-grade B-cell non-Hodgkin lymphomas

The vast spectrum of aggressive B-cell non-Hodgkin neoplasms (B-NHL) encompasses several infrequent entities occurring in association with viral infections, posing diagnostic challenges for practitioners. In the emerging era of precision oncology, the molecular characterization of malignancies has acquired paramount significance. The pathophysiological comprehension of specific entities and the identification of targeted therapeutic options have seen rapid development. However, owing to their rarity, not all entities have undergone exhaustive molecular characterization. Considerable heterogeneity exists in the extant body of work, both in terms of employed methodologies and the scale of cases studied. Presently, therapeutic strategies are predominantly derived from observations in diffuse large B-cell lymphoma (DLBCL), the most prevalent subset of aggressive B-NHL. Ongoing investigations into the molecular profiles of these uncommon virus-associated entities are progressively facilitating a clearer distinction from DLBCL, ultimately paving the way towards individualized therapeutic approaches. This review consolidates the current molecular insights into aggressive and virus-associated B-NHL, taking into consideration the recently updated 5th edition of the WHO classification of hematolymphoid tumors (WHO-5HAEM) and the International Consensus Classification (ICC). Additionally, potential therapeutically targetable susceptibilities are highlighted, offering a comprehensive overview of the present scientific landscape in the field.

Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissues: B-cell Neoplasms

We review B-cell neoplasms in the 5th edition of the World Health Organization classification of hematolymphoid tumors (WHO-HEM5). The revised classification is based on a multidisciplinary approach including input from pathologists, clinicians, and other experts. The WHO-HEM5 follows a hierarchical structure allowing the use of family (class)-level definitions when defining diagnostic criteria are partially met or a complete investigational workup is not possible. Disease types and subtypes have expanded compared with the WHO revised 4th edition (WHO-HEM4R), mainly because of the expansion in genomic knowledge of these diseases. In this review, we focus on highlighting changes and updates in the classification of B-cell lymphomas, providing a comparison with WHO-HEM4R, and offering guidance on how the new classification can be applied to the diagnosis of B-cell lymphomas in routine practice.

CDC6 may serve as an indicator of lung adenocarcinoma prognosis and progression based on TCGA and GEO data mining and experimental analyses

Lung adenocarcinoma (LUAD) is one of the most lethal types of cancer worldwide, and accurately predicting patient prognosis is an important challenge. Gene prediction models, which are known for their simplicity and efficiency, have the potential to be used for prognostic predictions. However, the availability of models with true clinical value is limited. The present study integrated tissue sequencing and the clinical information of patients with LUAD from The Cancer Genome Atlas and Gene Expression Omnibus databases using bioinformatics. This comprehensive approach enabled the identification of 252 differentially expressed genes. Subsequently, univariate and multivariate Cox analyses were performed using these genes, and 14 and 3 genes [including cell division cycle 6 (CDC6), hyaluronan mediated motility receptor and STIL centriolar assembly protein] were selected for the construction of two prognostic models. Notably, the 3‑gene prognostic model exhibited a comparable predictive ability to that of the 14‑gene model. Functionally, pathway enrichment analysis revealed that CDC6 played a role in regulating the cell cycle and promoting tumor staging. To further investigate the relevance of CDC6, in vitro experiments involving the downregulation of CDC6 expression were conducted, which resulted in significant inhibition of tumor cell migration, invasion and proliferation. Moreover, in vivo experiments demonstrated that downregulating CDC6 expression significantly reduced the burden and metastasis of in situ lung tumors in mice. These findings suggested that CDC6 may be a critical gene involved in the development and prognosis of LUAD. In summary, the present study successfully constructed a simple yet accurate prognostic prediction model consisting of 3 genes. Additionally, the functional importance of CDC6 as a key gene in the model was identified. These findings lay a crucial foundation for further exploration of prognostic prediction models and a deeper understanding of the functional mechanisms of CDC6. Notably, these results have potential clinical implications for improving personalized treatment and prognosis evaluation for patients with LUAD.

A rare case of fluid overload-associated large B-cell lymphoma and antigen loss at relapse

Fluid overload-associated large B-cell lymphoma (FO-LBCL) is a new addition to the list of large B-cell lymphomas in the 5th edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5). This report presents an unusual case of FO-LBCL with partial B cell antigen loss at relapse and reviews the characteristics, treatment, and prognosis of these patients to enhance our understanding of this disease. Immunophenotyping was performed through immunohistochemistry and flow cytometry. Immunoglobulin gene rearrangements were analyzed using BIOMED-2 multiplex primers. MYC, BCL2, and BCL6 gene rearrangements were detected by fluorescent in situ hybridization (FISH). Cell-free DNA (cfDNA) from pleural effusion and peripheral blood was subjected to somatic mutation evaluation using next-generation sequencing (NGS). In 2020, the patient was initially diagnosed with tuberculous pleurisy and received anti-tuberculous drugs. Subsequent testing of the pleural effusion cell block revealed that the large cells to be positive for CD10, CD20, CD79a, PAX5, MUM1, Bcl-2, Bcl-6, and c-myc and negative for CD3, CD30, Cyclin D1, and HHV8. In situ hybridization for Epstein-Barr virus (EBV)-associated mRNA (EBER-ISH) was negative. Additionally, a clonal rearrangement of immunoglobulin heavy locus (IGH) FR2-JH was detected; the results of MYC, BCL2, and BCL6 gene rearrangements were all negative. Following pleural drainage treatment, the patient achieved symptom remission and was diagnosed with large B-cell lymphoma (HHV8-unrelated PEL-like lymphoma). In 2022, the patient was readmitted due to the recurrence of pleural effusion. The pleural effusion cell block revealed a distinct immunophenotype compared to previous findings, positivity for PAX5 and negativity for CD20, CD10, CD3, CD5, CD30, CD38, CD138, CD79a, MUM1, Bcl-2, Bcl-6, Cyclin D1, c-myc, ALK, and HHV8. Identical IGH FR2-JH clonal rearrangement suggested the recurrence of the original clone. CfDNA analysis showed mutations in CD79B, MYD88, CCND3, and DTX1. The patient was ultimately diagnosed with FO-LBCL based on the WHO-HAEM5 classification. Diagnosis of FO-LBCL should be differentiated from primary effusion lymphoma (PEL). The features of this case align with the description of "FO-LBCL" in WHO-HAEM5 and "HHV8 and EBV-negative primary effusion-based lymphoma" in International Consensus Classification (ICC). FO-LBCL patients generally have a more favorable prognosis compared to PEL. In this case, the patient exhibited a favorable prognosis for over 22 months without additional treatment apart from pleural drainage.

Development and validation of nomogram prognostic model for predicting OS in patients with diffuse large B-cell lymphoma: a cohort study in China

This study comprehensively incorporates pathological parameters and novel clinical prognostic factors from the international prognostic index (IPI) to develop a nomogram prognostic model for overall survival in patients with diffuse large B-cell lymphoma (DLBCL). The aim is to facilitate personalized treatment and management strategies. This study enrolled a total of 783 cases for analysis. LASSO regression and stepwise multivariate COX regression were employed to identify significant variables and build a nomogram model. The calibration curve, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) curve were utilized to assess the model's performance and effectiveness. Additionally, the time-dependent concordance index (C-index) and time-dependent area under the ROC curve (AUC) were computed to validate the model's stability across different time points. The study utilized 8 selected clinical features as predictors to develop a nomogram model for predicting the overall survival of DLBCL patients. The model exhibited robust generalization ability with an AUC exceeding 0.7 at 1, 3, and 5 years. The calibration curve displayed evenly distributed points on both sides of the diagonal, and the slopes of the three calibration curves were close to 1 and statistically significant, indicating high prediction accuracy of the model. Furthermore, the model demonstrated valuable clinical significance and holds the potential for widespread adoption in clinical practice. The novel prognostic model developed for DLBCL patients incorporates readily accessible clinical parameters, resulting in significantly enhanced prediction accuracy and performance. Moreover, the study's use of a continuous general cohort, as opposed to clinical trials, makes it more representative of the broader lymphoma patient population, thus increasing its applicability in routine clinical care.

Cavity-based lymphomas: challenges and novel concepts. A report of the 2022 EA4HP/SH lymphoma workshop

The 2022 European Association for Haematopathology/Society for Hematopathology lymphoma workshop session on cavity-based lymphomas included sixty-eight cases in seven sections. The disease entities discussed include primary effusion lymphomas (PEL), extracavitary primary effusion lymphomas and confounding entities (ECPEL), HHV8-negative B-lineage lymphomas-effusion based (EBV-negative, EBV-positive, and plasmablastic types), diffuse large B-cell lymphoma associated with chronic inflammation, fibrin-associated diffuse large B-cell lymphoma (FA-DLBCL), breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), and other lymphomas presenting as an effusion. All entities above are discussed; however, three are delved into greater detail given the challenges with classification: ECPEL, HHV8-negative effusion-based lymphomas, and FA-DLBCL. Cases exemplifying the diagnostic difficulty in differentiating ECPEL from HHV8-positive diffuse large B-cell lymphoma and germinotropic lymphoproliferative disorder were discussed. The more recently recognized effusion-based HHV8-negative large B-cell lymphoma is explored, with several cases submitted raising the question if this subset should be carved out as a specific entity, and if so, what should be the refining diagnostic criteria. Case submissions to the FA-DLBCL section yielded one of the largest case series to date, including classic cases, cases furthering the discussion on disease sites and prognosis, as well as novel concepts to be considered in this entity. The 2022 EA4HP/SH workshop cases allowed for further confirmation of the characteristics of some of the more historically accepted cavity-based lymphomas, as well as further inquiry and debate on relatively new or evolving entities.

Primary Effusion Lymphoma-like Lymphoma Mimicking Tuberculous Pleural Effusion: Three Case Reports and a Literature Review

Primary effusion lymphoma-like lymphoma (PEL-LL) is a rare lymphoma, localized in the body cavity without detectable tumor masses. Tuberculous pleural effusion is a form of extra pulmonary tuberculous. We herein report three cases of PEL-LL in patients with a history of pulmonary tuberculosis. Despite the presentation with lymphocyte predominance and high levels of adenosine deaminase, a notable characteristic of tuberculous pleural effusion, the patients were ultimately diagnosed with PEL-LL. Pleural fluid laboratory tests yield similar results for PEL-LL and tuberculous pleural effusion; therefore, cytological and immunophenotyping examinations are useful for their differential diagnosis and the determination of treatment.

Fluid Overload-Associated Large B-Cell Lymphoma: A Case Report and Review of Literature

Fluid overload-associated large B-cell lymphoma (FO-LBCL) is a new entity described in the fifth edition of the World Health Organization (WHO) Classification of Hematolymphoid Tumors (WHO-HAEM5). It refers to malignant lymphoma present with symptoms of serous effusions in body cavities (pleural, peritoneal, and/or pericardial) in the absence of an identifiable tumor mass. We present a case of an 82-year-old man with a history of atrial fibrillation and atrial flutter, status post-ablation, essential hypertension (HTN), hyperlipidemia (HLD), and diabetes mellitus (DM) type 2 who was referred to our hospital for shortness of breath due to recurrent pleural effusion. Right video-assisted thoracoscopy with right pleural biopsy was performed. Histopathological examination of the pleural biopsy revealed dense fibrous tissue, chronic inflammation, lymphoid aggregates, and granulation tissue, with no evidence of lymphoma. Cytology of the right pleural fluid revealed large lymphoid cells, which were positive for CD45, CD20, PAX-5, MUM-1, BCL2, BCL6, and MYC protein. They were negative for CD3, CD10, CD138, and HHV-8 by immunohistochemistry (IHC). Epstein-Barr virus (EBV) was negative by in situ hybridization (ISH). Due to the absence of any evidence of lymphoma elsewhere, a diagnosis of fluid overload-associated large B-cell lymphoma (FO-LBCL) was made. We provide a synopsis of the main clinicopathological features of FO-LBCL and the two main differential diagnoses, primary effusion lymphoma (PEL) and diffuse large B-cell lymphoma (DLBCL).

HHV8 and EBV-negative primary effusion-based lymphoma: A case report of a new provisional entity and review of literature

Key Clinical Message

HHV8- and EBV-negative primary effusion lymphoma is an extremely rare neoplasm involving body cavities without detectable tumor mass. It usually presents in elderly patients without known immunodeficiency. Compared to primary effusion lymphoma, it has a better prognosis.

Primary effusion lymphoma (PEL) is a rare non-Hodgkin lymphoma confined exclusively to body cavities without detectable tumor masses. The term PEL-like is an entity similar to PEL in clinical presentation but without relation to human herpesvirus 8 (HHV8). We report a case of HHV8- and EBV-negative primary effusion-based lymphoma.

Large B-Cell Lymphomas in the 5th Edition of the WHO-Classification of Haematolymphoid Neoplasms-Updated Classification and New Concepts

The family/class of the large B-cell lymphomas (LBCL) in the 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumors (WHO-HAEM5) features only a few major changes as compared to the 4th edition. In most entities, there are only subtle changes, many of them only representing some minor modifications in diagnostic terms. Major changes have been made in the diffuse large B-cell lymphomas (DLBCL)/high-grade B-cell lymphomas (HGBL) associated with MYC and BCL2 and/or BCL6 rearrangements. This category now consists of MYC and BCL2 rearranged cases exclusively, while the MYC/BCL6 double hit lymphomas now constitute genetic subtypes of DLBCL, not otherwise specified (NOS) or of HGBL, NOS. Other major changes are the conceptual merger of lymphomas arising in immune-privileged sites and the description of LBCL arising in the setting of immune dysregulation/deficiency. In addition, novel findings concerning underlying biological mechanisms in the pathogenesis of the different entities are provided.

Fluid overload–associated large B-cell lymphoma with primary biliary cirrhosis: A case report

The 5th edition of World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5) is characterized by its hierarchical system for classification and novel entities/types. Considering the significant discrepancy in clinical manifestations and prognosis, fluid overload–associated large B-cell lymphoma (FOALBCL) has been a new addition to the WHO-HAEM5, being distinct from the traditional diagnosis of primary effusion lymphoma. In this manuscript, we report a patient who was diagnosed with FOALBCL that a novel entity introduced in the WHO-HAEM5. It is an instance of a successful application of the updated WHO-HAEM5 and indicates that the ′Blue Book′ could confer convenience and benefits on both patients and clinicians. Moreover, the patient combined primary biliary cirrhosis (PBC), which is a relatively rare condition compared to the underlying medical condition of viral cirrhosis. Due to atypical clinical symptoms and invasive biopsy of lymphoma, sometimes, diagnoses might be undesired, which eventually leads to a poor prognosis. With this case report, it reminds not just hematologists but also other specialists to pay attention to the updates and revisions of the classifications of lymphoma.

Primary Effusion Lymphoma in an HIV-Negative Patient with Chronic Myeloid Leukemia Treated with Dasatinib

INTRODUCTION

Primary effusion lymphoma (PEL) is a malignant lymphomatous effusion, which by definition is Kaposi sarcoma herpesvirus/human herpesvirus 8-positive. PEL typically occurs in HIV-infected patients but can also occur in HIV-negative individuals, including in organ transplant recipients. Tyrosine kinase inhibitors (TKIs) are currently the standard of care for patients with chronic myeloid leukemia (CML), BCR::ABL1-positive. Although TKIs are extremely effective in treating CML, they alter T-cell function by inhibiting peripheral T-cell migration and altering T-cell trafficking and have been associated with the development of pleural effusions.

CASE PRESENTATION

We report a case of PEL in a young, relatively immunocompetent patient with no history of organ transplant receiving dasatinib for CML, BCR::ABL1-positive.

DISCUSSION

We hypothesize that the loss of T-cell function secondary to TKI therapy (dasatinib) may have resulted in the unchecked cellular proliferation of Kaposi sarcoma herpesvirus (KSHV)-infected cells, leading to the emergence of a PEL. We recommend cytologic investigation and KSHV testing in patients being treated with dasatinib for CML who present with persistent or recurrent effusions.

Diffuse large B-cell lymphomas, not otherwise specified, and emerging entities

Diffuse large B-cell lymphoma (DLBCL) is an aggressive and heterogenous group of diseases and the most common subtype of non-Hodgkin lymphoma. In the past decade, there has been an explosion in molecular profiling that has helped to identify subgroups and shared oncogenic driving mechanisms. Since the 2017 World Health Organization (WHO) classification, additional studies investigating these genomic abnormalities and phenotypic findings have been reported. Here we review these findings in DLBCL and address the proposed changes by the 2022 International Consensus Classification.

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.

Targeting VEGF with bevacizumab inhibits malignant effusion formation of primary human herpesvirus 8‐unrelated effusion large B‐cell lymphoma in vivo

Primary human herpesvirus 8 (HHV8)‐unrelated effusion large B‐cell lymphoma (ELBCL) is recognized as a new clinical entity, but its pathogenesis and therapeutic strategies remain largely unknown. We have generated two mouse models with profuse lymphomatous effusions that resemble HHV8‐unrelated ELBCL occurring in humans, by grafting the cell lines designated as Pell‐1 and Pell‐2. Using these in vivo models, we evaluated the potential role of vascular endothelial growth factor (VEGF) in the pathogenesis of HHV8‐unrelated ELBCL. Both Pell‐1 and Pell‐2 cells consistently produced very high levels of VEGF in mice, in contrast to in vitro findings of relatively low VEGF production in culture medium by HHV8‐unrelated ELBCL cells, especially Pell‐1 cells. Conversely, returning Pell‐1 cells grown in mice to culture medium markedly suppressed VEGF production to the original in vitro level. These findings suggest that the tumour microenvironment plays a role in the steady production of VEGF. We also found that the interaction between HHV8‐unrelated ELBCL cells and peritoneal mesothelial cells increased the production of VEGF in vitro. Finally, we found that bevacizumab significantly suppressed effusion formation and lymphoma cell growth in both mouse models. These results suggest that bevacizumab is a rational approach to the treatment of HHV8‐unrelated ELBCL.

Human herpesvirus 8-negative effusion-based large B-cell lymphoma: a distinct entity with unique clinicopathologic characteristics

Rare cases of human herpesvirus 8 (HHV8)-negative effusion-based large B-cell lymphoma (EB-LBCL) occur in body cavities without antecedent or concurrent solid mass formation. In contrast to HHV8 + primary effusion lymphoma (PEL), EB-LBCL has no known association with HIV or HHV8 infection. However, the small sample sizes of case reports and series worldwide, especially from non-Japanese regions, have precluded diagnostic uniformity. Therefore, we conducted a retrospective, multi-institutional study of 55 cases of EB-LBCL and performed a comprehensive review of an additional 147 cases from the literature to identify distinct clinicopathologic characteristics. In our study, EB-LBCL primarily affected elderly (median age 80 years), immunocompetent patients and manifested as lymphomatous effusion without a solid component. The lymphomatous effusions mostly occurred in the pleural cavity (40/55, 73%), followed by the pericardial cavity (17/55, 31%). EB-LBCL expressed CD20 (53/54, 98%) and PAX5 (23/23, 100%). Most cases (30/36, 83%) were of non-germinal center B-cell subtype per the Hans algorithm. HHV8 infection was absent (0/55, 0%), while Epstein-Barr virus was detected in 6% (3/47). Clinically, some patients were managed with drainage alone (15/34, 44%), while others received rituximab alone (4/34, 12%) or chemotherapy (15/34, 44%). Eventually, 56% (22/39) died with a median overall survival (OS) of 14.9 months. Our findings were similar to those from the literature; however, compared to the non-Japanese cases, the Japanese cases had a significantly higher incidence of pericardial involvement, a higher rate of chemotherapy administration, and longer median OS. Particularly, we have found that Japanese residence, presence of pericardial effusion, and absence of MYC rearrangement are all favorable prognostic factors. Our data suggest that EB-LBCL portends a worse prognosis than previously reported, although select patients may be managed conservatively. Overall, EB-LBCL has distinct clinicopathologic characteristics, necessitating the establishment of separate diagnostic criteria and consensus nomenclature.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Development of a novel cell line-derived xenograft model of primary herpesvirus 8-unrelated effusion large B-cell lymphoma and antitumor activity of birabresib in vitro and in vivo

BACKGROUND

Primary human herpesvirus 8 (HHV8)-unrelated effusion large B-cell lymphoma is a clinical disease entity distinct from HHV8-positive primary effusion lymphoma (PEL). However, the lack of experimental HHV8-unrelated effusion large B-cell lymphoma models continues to hinder the pathophysiologic and therapeutic investigations of this disorder.

METHODS

The lymphoma cells were obtained from the pleural effusion of a patient with primary HHV8-unrelated effusion large B-cell lymphoma and cultured in vitro.

RESULTS

We established a novel HHV8-unrelated effusion large B-cell lymphoma cell line, designated Pell-1, carrying a c-MYC rearrangement with features distinct from those of HHV8-positive PEL. Moreover, we developed an HHV8-unrelated effusion large B-cell lymphoma cell line-derived xenograft model. Pell-1 cells induced profuse lymphomatous ascites and subsequently formed intra-abdominal tumors after intraperitoneal implantation into irradiated nonobese diabetic/severe combined immunodeficient mice. Thus, this xenograft mouse model mimicked the clinical phenomena observed in patients and recapitulated the sequential stages of aggressive HHV8-unrelated effusion large B-cell lymphoma. The bromodomain and extraterminal domain (BET) inhibitors JQ1 and birabresib (MK-8628/OTX015) reduced the proliferation of Pell-1 cells in vitro through the induction of cell cycle arrest and apoptosis. The antitumor effect of BET inhibition was also demonstrated in vivo, as birabresib significantly reduced ascites and suppressed tumor progression without apparent adverse effects in the xenografted mice.

CONCLUSION

These preclinical findings suggest the therapeutic potential of targeting c-MYC through BET inhibition in HHV8-unrelated effusion large B-cell lymphoma.

Primary HHV-8 (-) Effusion-Based Non-Germinal Center B Cell Diffuse Large B Cell Lymphoma Successfully Treated with Standard Anthracycline-Based Chemoimmunotherapy

Effusion-based lymphomas (EBL) are usually high-grade B cell non-Hodgkin’s lymphomas which involve effusion fluid in a body cavity, typically presenting as a pleural effusion, without evidence of disease elsewhere. They are most frequently seen in HIV-infected individuals and are biologically driven by human herpesvirus-8 virus (HHV-8). HHV-8 (+) EBL is recognized as primary effusion lymphoma (PEL) under the World Health Organization classification. HHV-8 (-) EBL has been reported in association with Hepatitis C virus (HCV) infection, Epstein-Barr virus (EBV) infection, fluid overload, liver cirrhosis, renal dysfunction, cardiac arrhythmias, myocardial infarction, and heart failure. These cases can be labeled as primary EBL (PEBL). We describe a non-germinal center B cell diffuse large B cell lymphoma (NGCB-DLBCL) presenting as PEBL in an immunocompetent 81-year-old male who had an extensive cardiac history and tested negative for HIV, HHV-8, and EBV. He was treated with thoracentesis and standard anthracycline-based chemoimmunotherapy and has remained in complete remission for over 5 ½ years since his original diagnosis. Our case indicates that NGCB-DLBCL can present as PEBL and is potentially curable with the standard chemoimmunotherapeutic approach.

Primary age-related EBV-associated effusion-based lymphoma successfully treated with rituximab and thoracentesis

EBV-positive HHV8-negative EBL is part of the spectrum of EBV-positive diffuse large B-cell lymphoma NOS. This entity can be labeled as primary age-related EBV-associated EBL and appears to respond well to rituximab and thoracentesis.

Primary Pulmonary B-Cell Lymphoma: A Review and Update

Simple Summary

The group of B-cell lymphomas primarily involving the lung encompasses different histological entities with distinct biological aspects, while sharing some clinical and radiological features related to their common anatomic site of occurrence. Recent molecular advances in the molecular genetics of these lesions have substantially improved of our understanding of the mechanisms of lymphomagenesis, adding novel information to histology in order to better characterize and manage these diseases. This review summarizes the available clinical, radiological, pathological, and molecular data on primary pulmonary B-cell lymphomas, discusses the mechanisms of lymphomagenesis, and highlights the role of a multi-disciplinary management in overcoming the diagnostic and therapeutic challenges in this setting.

Abstract

Primary pulmonary B-cell lymphomas (PP-BCLs) comprise a group of extranodal non-Hodgkin lymphomas of B-cell origin, which primarily affect the lung without evidence of extrapulmonary disease at the time of diagnosis and up to 3 months afterwards. Primary lymphoid proliferations of the lung are most often of B-cell lineage, and include three major entities with different clinical, morphological, and molecular features: primary pulmonary marginal zone lymphoma of mucosa-associated lymphoid tissue (PP-MZL, or MALT lymphoma), primary pulmonary diffuse large B cell lymphoma (PP-DLBCL), and lymphomatoid granulomatosis (LYG). Less common entities include primary effusion B-cell lymphoma (PEL) and intravascular large B cell lymphoma (IVLBCL). A proper workup requires a multidisciplinary approach, including radiologists, pneumologists, thoracic surgeons, pathologists, hemato-oncologists, and radiation oncologists, in order to achieve a correct diagnosis and risk assessment. Aim of this review is to analyze and outline the clinical and pathological features of the most frequent PP-BCLs, and to critically analyze the major issues in their diagnosis and management.

Cytogenetic complexity and heterogeneity in intravascular lymphoma

AIMS

To characterise the karyotypic abnormalities and heterogeneities in intravascular lymphoma (IVL).

METHODS

G-banded karyotyping was performed on biopsy specimens from a single-centre IVL cohort comprising intravascular large B-cell lymphoma (IVLBCL, n=12) and NK/T-cell lymphoma (IVNKTCL, n=1).

RESULTS

Five IVLBCL cases and one IVNKTCL case (total 46%) were found to have normal karyotypes, and the cytogenetic abnormalities observed in the other seven IVLBCL cases (54%) were investigated further. These seven karyotypes were uniformly complex with an average of 13 aberrations. The seven cases all had abnormalities involving chromosome 6, with 57% involving structural abnormalities at 6q13, and chromosome 8, with 43% involving abnormalities at 8p11.2. In addition, 71% had aberrations at 19q13. On average, 4.4 chromosomal gains and losses were detected per case. Cytogenetic heterogeneities were observed in six cases (86%) and tetraploidy in three cases (43%). There was no significant difference in progression-free survival (p=0.92) and overall survival (p=0.61) between the IVLBCL cases with complex and normal karyotypes.

CONCLUSION

Approximately half of IVLBCL cases had a highly heterogeneous pattern of karyotypes with different clonal numerical and structural chromosome aberrations.

Lymphomas arising in immune-privileged sites: insights into biology, diagnosis, and pathogenesis

Session 2 of the 2018 European Association of Hematopathology/Society for Hematopathology Workshop focused on lymphomas arising in immune-privileged sites: both lymphomas arising in the traditionally described "immune sanctuary" sites of the central nervous system (CNS) and testes, as well as those arising at sites of local immune privilege. Primary CNS large B cell lymphoma and primary testicular large B cell lymphoma were discussed, and the biology of these unique tumors was highlighted by several cases showing the classic mutation profile including MYD88 L265P and CD79B. The tendency of these tumors to involve both the CNS and testis was also reinforced by several cases. Four cases of low-grade B cell lymphomas (LGBCL) of the CNS were discussed. Two were classic Bing-Neel syndrome associated with LPL, and two were LGBCL with plasmacytic differentiation and amyloid deposition without systemic disease. Rare examples of systemic T and NK cell lymphomas involving the CNS were also discussed. Several cases of breast implant-associated anaplastic large cell lymphoma (BI-ALCL) were submitted showing the typical clinicopathologic features. These cases were discussed along with a case with analogous features arising in a patient with a gastric band implant, as well as large B cell lymphomas arising alongside foreign materials. Finally, large B cell lymphomas arising in effusions or localized sites of chronic inflammation (fibrin-associated diffuse large B cell lymphoma [DLBCL] and DLBCL associated with chronic inflammation) were described. The pathogenesis of all of these lymphomas is believed to be related to decreased immune surveillance, either innate to the physiology of the organ or acquired at a local site.