Human herpesvirus 8-unrelated primary effusion lymphoma-like lymphoma: report of a rare case and review of 54 cases in the literature

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.

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).

Where has the lymphoma gone? Pericardial effusion adenosine deaminase may play a key role in diagnosing primary effusion lymphoma-like lymphoma: a case report

Background

Primary effusion lymphoma (PEL) is a non-Hodgkin lymphoma that is exclusively generated by body cavity effusion. Primary effusion lymphoma develops in patients infected with human immunodeficiency virus (HIV) and is associated with the human herpes virus (HHV)-8 infection. However, there are sporadic cases without HHV-8 infections or any history of immunodeficiency, called 'PEL-like lymphoma'.

Case summary

An 83-year-old man was admitted to our institution because of shortness of breath, fatigue, and facial oedema. Laboratory findings were unremarkable, including negative results for HIV antibodies. Transthoracic echocardiography revealed massive pericardial effusion surrounding the entire heart, which resulted in the early diastolic collapse of the right ventricular free wall, indicating elevated intra-pericardial pressure. He underwent pericardial centesis and 700 mL of pericardial fluid was drained. Adenosine deaminase (ADA) in the pericardial effusion showed an abnormally high value of 221 U/L. Cytological examination revealed a cellular population compatible with diffuse large B-cell lymphoma with prominent blastic characteristics and negative for HHV-8 latent nuclear antigens. Thus, the patient was diagnosed with HHV-8 unrelated HIV-negative PEL-like lymphoma. He was followed for more than 10 months in complete remission after a single pericardial drainage without any chemotherapy.

Discussion

Exhaustive drainage of the lymphomatous effusion may induce complete remission in some patients with PEL-like lymphoma. Furthermore, the ADA value in the pericardial effusion may serve as a valuable guide to facilitate the accurate diagnosis of PEL-like lymphoma.

HHV8-unrelated primary effusion lymphoma in a patient with HBV-related liver cirrhosis: A case successfully treated with rituximab and lenalidomide

Human herpesvirus type 8 (HHV-8) unrelated primary effusion lymphoma (PEL) like lymphoma (PEL-LL) is an exceedingly rare non-Hodgkin lymphoma with no characteristic symptoms and consensus on the optimal treatment. This case report presents a 55-year-old man with prior HBV-related Child-Pugh B liver cirrhosis and developing activity-related dyspnea. A moderate amount of pleural effusion was identified without tumor masses, and cytological studies confirmed a diagnosis of PEL-LL. The patient received rituximab and lenalidomide, albeit with HBV infection, and is currently on maintenance therapy with resolving symptoms but without HBV reactivation. Hence, the R2 protocol (rituximab and lenalidomide) might be clinically effective and safe for PEL-LL patients with HBV infection and Child-Pugh B liver cirrhosis.

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.

Spontaneous regression of dasatinib-related primary effusion lymphoma-like lymphoma

Primary effusion lymphoma-like lymphoma (PEL-LL) shows a unique clinical presentation, characterized by lymphomatous effusions in the body cavities. PEL-LL may be associated with hepatitis C virus infections and fluid overload states; and owing to its rarity, no standard therapies have been established. We report a case of a 55-year-old woman who developed PEL-LL during treatment with dasatinib, for chronic myeloid leukemia (CML). She presented to our hospital with dyspnea lasting for approximately a month and showed pericardial and bilateral pleural effusions. The pericardial effusion was exudative, and cytopathological and immunophenotypic examinations showed numerous CD 20-positive, large atypical lymphoid cells, which were also positive for the Epstein-Barr virus gene. No evidence of lymphadenopathy or bone marrow infiltration was found. We diagnosed PEL-LL, immediately discontinued dasatinib, and performed continuous drainage of the pericardial effusions. Complete response was achieved, and remission was maintained for 15 months. Two months after discontinuation of dasatinib, she was administered imatinib and a deep molecular response for the CML was maintained. PEL-LL occurring during dasatinib treatment is rare. We compared the results of previous reports with this case, and found that early diagnosis of PEL-LL, discontinuation of dasatinib, and sufficient drainage can improve the prognosis of PEL-LL.

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.

Primary Effusion Lymphoma: A Timely Review on the Association with HIV, HHV8, and EBV

Primary effusion lymphoma (PEL) is defined by the WHO classification as a large B-cell neoplasm without detectable tumor masses. It is universally associated with HHV8, with most cases occurring in the setting of immunodeficiency such as HIV infection, and a poor prognosis. Morphologically, the neoplastic cells range from immunoblastic, plasmablastic, to anaplastic; and phenotypically, most cases express plasma cell but not B-cell markers, i.e., plasmablastic. During the past decade, primary HHV8-negative effusion lymphoma has been reported. Such cases were considered in the WHO classification scheme as effusion-based lymphoma. We performed a systemic review of 167 HHV8-negative effusion lymphomas from the literature and found that only 42% were associated with a fluid overload state, and with low rates of HIV (6%) or EBV (21%) infection. Furthermore, most patients are old (or immunosenescent) with underlying medical conditions/comorbidities, most neoplasms are of B-cell phenotype, and the outcome is more favorable than that of HHV8-positive PEL. These distinctive findings supported our prior proposal of designating these HHV8-negative cases as type II PEL, in contrast to the classic or type I PEL as defined by the WHO. Furthermore, we propose an algorithmic approach for the diagnosis of PEL and its mimickers.

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 human herpesvirus 8-negative effusion-based lymphoma: a large B-cell lymphoma with favorable prognosis

Primary effusion-based lymphoma (EBL) presents as a malignant effusion in a body cavity. The clinicopathologic features and prognosis of primary human herpesvirus 8 (HHV8)-negative EBL remain unclear. We therefore conducted a retrospective study of 95 patients with EBL, regardless of HHV8 status, in Japan. Of 69 patients with EBL tested for HHV8, a total of 64 were negative. The median age of patients with primary HHV8-negative EBL at diagnosis was 77 years (range, 57-98 years); all 58 tested patients were negative for HIV. Primary HHV8-negative EBL was most commonly diagnosed in pleural effusion (77%). Expression of at least 1 pan B-cell antigen (CD19, CD20, or CD79a) was observed in all cases. According to the Hans algorithm, 30 of the 38 evaluated patients had nongerminal center B-cell (non-GCB) tumors. Epstein-Barr virus-encoded small RNA was positive in 6 of 45 patients. In 56 of 64 HHV8-negative patients, systemic therapy was initiated within 3 months after diagnosis. Cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) or CHOP-like regimens with or without rituximab (n = 48) were the most common primary treatments. The overall response and complete response rates were 95% and 73%, respectively. Three patients did not progress without systemic treatment for a median of 24 months. With a median 25-month follow-up, the 2-year overall survival and progression-free survival rates were 84.7% and 73.8%. Sixteen patients died; 12 were lymphoma-related deaths. Thus, most EBL cases in Japan are HHV8-negative and affect elderly patients. The non-GCB subtype is predominant. Overall, primary HHV8-negative EBL exhibits a favorable prognosis after anthracycline-based chemotherapy.

Human herpesvirus 8-negative effusion-based lymphoma with indolent clinical behavior in an elderly patient: A case report and literature review

Primary effusion lymphoma (PEL) is a B-cell non-Hodgkin's lymphoma that is usually characterized by lymphomatous effusions in the body cavity without any detectable tumor masses. According to the World Health Organization (WHO) schema for tumor classification, PEL is defined by the presence of human herpesvirus 8 (HHV8) in malignant lymphoid cells. However, a subset of effusion-based B-cell lymphoma is not HHV8-positive and exhibits different clinicopathological characteristics. The 2017 WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues does not list HHV8-negative effusion-based lymphoma, which remains an underappreciated B-cell lymphoma, as an individual entity. The present study reports a case of this rare type of lymphoma with indolent clinical behavior in a 75-year-old male patient receiving only symptomatic treatment. Additionally, a review of similar cases reported in the English literature is presented.

Lymphoid Neoplasms With Plasmablastic Differentiation: A Comprehensive Review and Diagnostic Approaches

Plasmablastic neoplasms encompass several entities including plasmablastic lymphoma, plasmablastic plasmacytoma/multiple myeloma, primary effusion lymphoma and its extracavitary variant, anaplastic lymphoma kinase-positive large B-cell lymphoma, and Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 (HHV8)-positive diffuse large B-cell lymphoma, not otherwise specified. Morphologically, the tumor cells are large with eccentrically located nuclei, prominent nucleoli, and basophilic/amphophilic cytoplasm. Immunophenotypically, the tumor cells express plasma cell-related antigens including CD38, CD138, interferon regulatory factor-4 (IRF4)/MUM1, PR domain zinc finger protein-1 (PRDM1), and/or X-box binding protein-1 (XBP1), with frequent loss of CD20. These tumors are diagnostically challenging for general pathologists due to their overlapping morphology and immunophenotype, and due to their rarity, and particularly so when clinical and radiologic information is insufficient. We also discuss HHV8-negative effusion-based lymphoma due to its overlapping features with primary effusion lymphoma. In this review, we focus on the useful diagnostic markers and pertinent molecular findings in these distinct entities and propose a practical diagnostic algorithm using anaplastic lymphoma kinase, HHV8, in situ hybridization for Epstein-Barr virus-encoded small RNA, immunoglobulin M, light chain stains, and clinicoradiologic criteria to avoid misdiagnosis. At the molecular level, MYC protein overexpression with or without MYC rearrangement and PRDM1-inactivating mutations or deletions are noted in a subset of such tumors, especially in plasmablastic lymphoma. Prognosis in these entities is dismal with conventional CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy. Therefore, novel target therapies, such as anti-CD30 agents, and/or immune blockade therapy, are potential treatment options in the future.

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

Human herpes virus-8 (HHV-8)-negative effusion-based lymphoma (HHV-8-negative EBL) can be distinguished from primary effusion lymphoma based on clinical and pathologic findings. Although the morphology between the 2 is similar and they both originate from body cavities with serous effusions and are characterized by lack of tumor masses, HHV-8-negative EBL generally occurs in older patients, and has favorable response to therapy and better prognosis than primary effusion lymphoma. However, no systematic studies have investigated prognostic factors in patients with HHV-8-negative EBL. In this report, clinical and pathologic characteristics of 67 cases of HHV-8-negative EBL, including 2 of our own cases, were analyzed. Univariate analyses revealed older age (70 y and above), Japanese ethnicity, pericardial effusion, CD20 expression, and chemotherapy with rituximab were significantly favorable prognostic factors. Peritoneal effusion was identified as an unfavorable prognostic factor. In the multivariate analysis, age and CD20 expression were independent prognostic factors (P=0.013 and 0.003, respectively). A past history of induced fluid overload, hepatitis C viral infection, and peritoneal effusion were significantly correlated with patients aged below 70 years, while pericardial and pleural effusions were significantly correlated with patients aged 70 years and above. A comparison of cases with and without CD20 expression revealed that Japanese ethnicity and pericardial effusion were significantly correlated with CD20 expression, whereas a past history of induced fluid overload and peritoneal effusion were significantly correlated with the absence of CD20. We concluded that older age and CD20 expression are significant and favorable independent prognostic factors of HHV-8-negative EBL.

EBV-Associated Lymphoproliferative Disorders: Update in Classification

Although about 90% of the world's population is infected by EBV only a small subset of the related infections result in neoplastic transformation. EBV is a versatile oncogenic agent involved in a multitude of hematopoietic, epithelial, and mesenchymal neoplasms, but the precise role of EBV in the pathogenesis of many of the associated lymphoid/histiocytic proliferations remains hypothetical or not completely understood. Additional studies and use of evolving technologies such as high-throughput next-generation sequencing may help address this knowledge gap and may lead to enhanced diagnostic assessment and the development of potential therapeutic interventions.

Body Cavity-Based Lymphoma in a Country with Low Human Immunodeficiency Virus Prevalence: A Series of 17 Cases from the Consortium for Improving Survival of Lymphoma

Purpose

Primary effusion lymphoma (PEL) is a type of body cavity–based lymphoma (BCBL). Most patients with PEL are severely immunocompromised and seropositive for human immunodeficiency virus (HIV). We investigated the distinctive clinicopathologic characteristics of BCBL in a country with low HIV burden.

Materials and Methods

We retrospectively collected data on the clinicopathologic characteristics, treatments, and outcomes of 17 consecutive patients with BCBL at nine institutions in Korea.

Results

Latency-associated nuclear antigen 1 (LANA1) immunostaining indicated that six patients had PEL, six patients had human herpesvirus 8 (HHV8)-unrelated BCBL, and five patients had HHV8-unknown BCBL. The patients with PEL exhibited no evidence of immunodeficiency except for one who was HIV positive. One (20%) and four (80%) patients with PEL and six (100%) and zero (0%) patients with HHV8-unrelated BCBL were positive for CD20 and CD30 expression, respectively. The two patients with PEL (one HIV-positive and one HIV-negative patient) with the lowest proliferation activity as assessed by the Ki-67 labeling index survived for > 1 and > 4 years without chemotherapy, respectively, in contrast to the PEL cases in the literature, which mostly showed a high proliferation index and poor survival.

Conclusion

PEL mostly occurred in ostensibly immunocompetent individuals and had a favorable outcome in Korea. A watchful waiting approach may be applicable for managing HIV-seronegative patients with PEL with a low Ki-67 labeling index. A possible trend was detected among LANA1, CD20, and CD30 expression in BCBL.

Indolent primary effusion lymphoma-like lymphoma in the pericardium: A case report and review of the literature

We report a rare case of a 75-year-old man with a history of mild-to-moderate pericardial effusion that was detected on echocardiography performed in October 2011 when the patient was 69 years old. Follow-up echocardiography was performed every 6 months thereafter, showing that the pericardial effusion gradually subsided. However, in April 2017 he started experiencing several episodes of dyspnea, which prompted him to visit our hospital's outpatient department on June 22, 2017. Echocardiography revealed a large amount of pericardial effusion; thus, he was immediately hospitalized. After undergoing pericardiocentesis and drainage, 1740-ml of bloody pericardial fluid was collected. Serum antibody tests for human immunodeficiency virus, hepatitis C virus, and human herpes virus 8 were negative, whereas that for Epstein-Barr virus (EBV) was positive, indicating a prior infection. Cytopathological examination, immunocytochemical staining, lymphocyte surface marker analysis, and cytogenetic assessment were performed. EBV-encoded small ribonucleic acid in situ hybridization was negative. He was diagnosed with primary effusion lymphoma (PEL)-like lymphoma (LL) and was treated with 8 doses of rituximab 375 mg/m² over a 2-month period. He has remained in complete response for the past 12 months. Our case shows the possibility of long-term existence of indolent PEL-LL in patients with mild-to-moderate pericardial effusion. <Learning objective: Primary effusion lymphoma (PEL)-like lymphoma (LL) is a rare disease with a poorly understood pathophysiology. Some patients are able to achieve a complete response after drainage of the effusion without chemotherapy. We experienced a case of PEL-LL, which was only diagnosed after 6 years of continually observing the pericardial effusion. Cardiologists should consider PEL-LL as a differential diagnosis in patients with unexplained pericardial effusion.>.

Biology and management of primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare B-cell malignancy that most often occurs in immunocompromised patients, such as HIV-infected individuals and patients receiving organ transplantation. The main characteristic of PEL is neoplastic effusions in body cavities without detectable tumor masses. The onset of the disease is associated with latent infection of human herpes virus 8/Kaposi sarcoma–associated herpes virus, and the normal counterpart of tumor cells is B cells with plasmablastic differentiation. A condition of immunodeficiency and a usual absence of CD20 expression lead to the expectation of the lack of efficacy of anti-CD20 monoclonal antibody; clinical outcomes of the disease remain extremely poor, with an overall survival at 1 year of ∼30%. Although recent progress in antiretroviral therapy has improved outcomes of HIV-infected patients, its benefit is still limited in patients with PEL. Furthermore, the usual high expression of programmed death ligand 1 in tumor cells, one of the most important immune-checkpoint molecules, results in the immune escape of tumor cells from the host immune defense, which could be the underlying mechanism of poor treatment efficacy. Molecular-targeted therapies for the activating pathways in PEL, including NF-κB, JAK/STAT, and phosphatidylinositol 3-kinase/AKT, have emerged to treat this intractable disease. A combination of immunological recovery from immune deficiency, overcoming the immune escape, and the development of more effective drugs will be vital for improving the outcomes of PEL patients in the future.

Epstein-Barr virus (EBV)-associated lymphoid proliferations, a 2018 update

Epstein-Barr virus (EBV) has been linked to many human neoplasms including hematopoietic, epithelial, and mesenchymal tumors. Since our original review of EBV-associated lymphoproliferative disorders in 2007, many advances and developments have been reported. In this review, we will examine the recent advances in EBV-associated lymphoid/histiocytic proliferations, dividing them into reactive, B cell, T/NK cell, immunodeficiency-related, and histiocytic/dendritic cell proliferations.

EBV-positive PEL-like lymphoma that developed in the course of antisynthetase syndrome treated with tacrolimus

Primary effusion lymphoma (PEL) is a rare type of extranodal lymphoma, typically of a B-cell origin, which presents as lymphomatous effusion with no nodal enlargement or tumor masses. The development PEL is universally associated with human herpes virus-8 (HHV-8) infection. Cases of HHV-8-negative primary lymphomatous effusion have recently been reported and referred to as HHV-8-unrelated PEL-like lymphoma. Some cases of this disease have been reported in iatrogenic immunocompromised patients. The mechanisms responsible for the inhibitory effects of the discontinuation of immunosuppressants other than methotrexate (MTX) against the disease, which have been demonstrated for MTX-associated lymphoproliferative disorders, have not yet been elucidated. We describe a case of PEL-like lymphoma that developed in the course of antisynthetase syndrome and was treated with tacrolimus. A single dose of systemic chemotherapy did not improve lymphomatous effusion, whereas the discontinuation of tacrolimus resulted in the long-term remission of this disease.

Primary effusion lymphoma in Taiwan shows two distinctive clinicopathological subtypes with rare human immunodeficiency virus association

AIMS

To investigate the clinicopathological and molecular features of primary effusion lymphoma (PEL) in Taiwan and the association with human immunodeficiency virus (HIV), human herpesvirus 8 (HHV8) and Epstein-Barr virus (EBV).

METHODS AND RESULTS

We investigated retrospectively 26 cases with a median age of 76.5. Only one (4%) patient was infected with HIV. Cytologically, all lymphoma cells revealed typical immunoblastic to plasmablastic morphology. Immunohistochemically, HHV8 was positive in eight (32%) tumours and negative in 17 (68%) cases. All 23 tested cases examined were of the non-germinal-centre B cell phenotype. MYC proto-oncogene (MYC) and Epstein-Barr encoding mRNA (EBER) were positive in 43% (nine of 21) and 17% (four of 23) cases, respectively. Immunoglobulin heavy chain (IGH), B cell lymphoma (BCL)2, BCL6 and MYC were rearranged in 71%, 11%, 12% and 18% cases, respectively. By univariate analysis, the overall survival (OS) was associated statistically with MYC expression (P = 0.012) and BCL2 rearrangement (P = 0.035), but not with the others. By multivariate analysis, no factor was statistically significant. Compared to the HHV8-negative cases, the HHV8-positive cases were mainly of the plasmablastic immunophenotype expressing CD30 and CD138, and with a less frequent expression of pan-B cell markers.

CONCLUSIONS

Apart from the phenotypical difference, our HHV8-positive neoplasms were not distinct from the HHV8-negative group. Literature review of 256 cases, including our cases, revealed that HHV8-positive cases were associated more frequently with HIV and EBV infection, with rare MYC rearrangement, and a poorer prognosis than HHV8-negative cases. We propose to name the HHV8-positive cases as 'classical' or 'type I PEL' and the HHV8-negative cases as 'type II PEL', stressing the similarities and the distinctive features between these two groups.

Human herpes virus 8-unrelated primary effusion lymphoma-like lymphoma presenting with cardiac tamponade: A case report

RATIONALE

Primary effusion lymphoma (PEL) is a rare disease of lymphomatous effusion in the body cavities in the absence of detectable mass and lymphadenopathy. PEL is predominantly related to the immunosuppressed patients infected with human herpes virus 8 (HHV-8). PEL-like lymphoma is negative for HHV-8 and human immunodeficiency virus (HIV) unlike PEL. The pathogenesis and prognosis of PEL-like lymphoma are unclear and there is no established treatment yet.

PATIENT CONCERNS

A 73-year-old male patient was admitted for evaluation of dyspnea on exertion with 1-week duration. His relevant examinations were completed.

DIAGNOSES

PEL-like lymphoma was diagnosed.

INTERVENTIONS

The patient received chemotherapy including rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), and palliative whole-brain radiotherapy, sequentially.

OUTCOMES

He died 3 months after the diagnosis.

LESSON

Although the prognosis of PEL-like lymphoma may be better than PEL, our case showed poor disease course despite chemotherapy.

A Case of Diffuse Large B-Cell Lymphoma Mimicking Primary Effusion Lymphoma-Like Lymphoma

A 93-year-old female was transferred to the emergency ward of our hospital due to disturbance of consciousness and hypotension. Computed tomography showed bilateral pleural and pericardial effusion without evidence of tumor masses or lymphadenopathy. Cytodiagnosis of pleural effusion revealed proliferation of atypical lymphoid-like cells with pan-B surface markers. We suspected primary effusion lymphoma-like lymphoma; however, the monoclonality of these cells was not confirmed. Cytodiagnosis of bone marrow revealed lymphoma cells with monoclonal B-cell markers. These findings prompted a diagnosis of diffuse large B-cell lymphoma with bone marrow invasion. In the case of pericardial or pleural effusion, clinicians should consider carefully both hematological malignancy and its classification.

Evidence for a Mesothelial Origin of Body Cavity Effusion Lymphomas

Background

Primary effusion lymphoma (PEL) is a Kaposi's sarcoma herpes virus (KSHV)-induced lymphoma that typically arises in body cavities of HIV-infected patients. PEL cells are often co-infected with Epstein-Barr virus (EBV). "PEL-like" lymphoma is a KSHV-unrelated lymphoma that arises in body cavities of HIV-negative patients. "PEL-like" lymphoma is sometimes EBV positive. The derivation of PEL/"PEL-like" cells is unclear.

Methods

Mesothelial cells were cultured from body cavity effusions of 23 patients. Cell proliferation, cytokine secretion, marker phenotypes, KSHV/EBV infection, and clonality were evaluated by standard methods. Gene expression was measured by quantitative polymerase chain reaction and immunoblotting. A mouse model of PEL (3 mice/group) was used to evaluate tumorigenicity.

Results

We found that the mesothelia derived from six effusions of HIV-infected patients with PEL or other KSHV-associated diseases contained rare KSHV + or EBV + mesothelial cells. After extended culture (16-17 weeks), some mesothelial cells underwent a trans-differentiation process, generating lymphoid-type CD45 + /B220 + , CD5 + , CD27 + , CD43 + , CD11c + , and CD3 - cells resembling "B1-cells," most commonly found in mouse body cavities. These "B1-like" cells were short lived. However, long-term KSHV + EBV - and EBV + KSHV - clonal cell lines emerged from mesothelial cultures from two patients that were clonally distinct from the monoclonal or polyclonal B-cell populations found in the patients' original effusions.

Conclusions

Mesothelial-to-lymphoid transformation is a newly identified in vitro process that generates "B1-like" cells and is associated with the emergence of long-lived KSHV or EBV-infected cell lines in KSHV-infected patients. These results identify mesothelial cultures as a source of PEL cells and lymphoid cells in humans.

B-cell lymphomas with discordance between pathological features and clinical behavior

B-cell lymphomas encompass a large number of disease entities clinically ranging from indolent to aggressive. The defining pathological features usually predict clinical course, with small and large B-cell lymphomas correlating to low-grade vs high-grade features, but discordant situations may be encountered. Two sessions of the workshop of the XVIII meeting of the European Association for Haematopathology (EAHP) held in Basel in 2016 addressed this topic. One session illustrated various facets of "aggressiveness" in indolent lymphomas, either peculiar clinical manifestations, cytological variants, or unusual genetic features, as well as several examples of progression or transformation to a more aggressive disease. Another session exemplified large B-cell lymphomas with unexpected indolent behavior including cases arising in well-defined body compartments or in sanctuary sites. This paper describes the features of the cases presented in both groups, highlights the most salient points of discussion raised by the submitters and the panel, and summarizes current knowledge and recommendations relevant to diagnostic pathology practice.

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.

Primary Effusion Lymphoma (PEL)-Like Lymphoma in a Child With Congenital Immunodeficiency

Primary effusion lymphoma (PEL) is a rare lymphoma that occurs more frequently in immunocompromised adults and has a poor survival. We report a 9-year-old female with combined immunodeficiency with an Epstein-Barr virus positive/human herpes virus 8 negative PEL-like lymphoma. The treatment with systemic chemotherapy for non-Hodgkin lymphoma, zidovudine, and interferon-α failed to control disease progression. This is the first reported pediatric case of PEL-like lymphoma. Increased diagnostic awareness and more effective treatment strategies are needed for this rare lymphoma.

Human Herpesvirus 8-Unrelated Primary Effusion Lymphoma-Like Lymphoma in an Elderly Korean Patient with a Good Response to Rituximab Plus Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin's lymphoma arising from a B-cell lineage characterized by the formation of malignant effusion in body cavities without evidence of a detectable tumor. The effusion contains tumor cells universally infected with human herpesvirus 8 (HHV8), which is the critical factor differentiating PEL from HHV8-unrelated PEL-like lymphoma (PEL-LL). This report describes a 77-year-old male patient with pleural effusion and ascites, containing lymphoma cells expressing a B-cell phenotype, but without markers of HHV8 in immunocytochemical analysis. The patient was diagnosed with PEL-LL and treated with six cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), which resulted in a complete remission. The patient is currently disease-free 15 months post-treatment. To the best of our knowledge, this is the first report on administration of R-CHOP in a PEL-LL patient in South Korea.

HHV-8-unrelated primary effusion-like lymphoma associated with clonal loss of inherited chromosomally-integrated human herpesvirus-6A from the telomere of chromosome 19q

Primary effusion lymphomas (PEL) are associated with human herpesvirus-8 (HHV-8) and usually occur in immunocompromised individuals. However, there are numerous reports of HHV-8-unrelated PEL-like lymphomas with unknown aetiology. Here we characterize an HHV-8-unrelated PEL-like lymphoma in an elderly woman who was negative for human immunodeficiency viruses 1 and 2, and hepatitis B and C. The woman was, however, a carrier of an inherited-chromosomally-integrated human herpesvirus-6A (iciHHV-6A) genome in one 19q telomere. The iciHHV-6A genome was complete in blood DNA, encoding a full set of protein-coding genes. Interestingly, the entire iciHHV-6A genome was absent from the HHV-8-unrelated-PEL-like lymphoma cells despite retention of both copies of chromosome 19. The somatic loss of the 19q-iciHHV-6A genome occurred very early during lymphoma development and we propose it occurred via telomere-loop formation and excision to release a circular viral genome that was subsequently lost. Whether release of the HHV-6A genome from the telomere contributed to lymphomagenesis, or was coincidental, remains unclear but this event may have deregulated the expression of HHV-6A or 19q genes or else disrupted telomere function. To establish the frequency and importance of iciHHV-6 loss from telomeres, the HHV-6 copy number should be assessed in tumours that arise in iciHHV-6 carriers.

CD4-Positive T-Cell Primary Central Nervous System Lymphoma in an HIV Positive Patient

OBJECTIVES

Primary central nervous system lymphomas (PCNSLs) in patients with human immunodeficiency virus (HIV) are predominantly B-cell lymphomas associated with Epstein-Barr virus (EBV) and rarely CD8-positive T-cell PCNSLs.

METHODS

Patient history, laboratory results, cerebrospinal fluid (CSF), imaging, and brain biopsy specimens were reviewed and tested for T-cell receptor clonality.

RESULTS

A 64-year-old HIV-positive woman sought treatment for lethargy and left-sided weakness. Brain imaging showed regional increased T2 signal with restricted diffusion in cerebral hemispheres. CSF flow cytometry revealed CD4-positive T lymphocytes with loss of CD3, CD5, and CD7. EBV-positive T-cell lymphoma was immunohistochemically confirmed on brain biopsy specimens. Molecular analysis detected clonal T-cell receptor gene rearrangement. The patient received intrathecal methotrexate and whole-brain radiation. She did not respond to treatment and was eventually placed in hospice care.

CONCLUSIONS

To our knowledge, this is the first report of CD4-positive T-cell PCNSL in an HIV-positive patient and will help to raise clinical awareness of this previously unknown entity.

Human herpesvirus-8-unrelated primary effusion lymphoma of the elderly not associated with an increased serum lactate dehydrogenase level: A benign sub-group of effusion lymphoma without chemotherapy

Human herpesvirus-8-unrelated primary effusion lymphoma characterized by lymphomatous effusion without nodal lesions occasionally exhibits spontaneous remission. To elucidate the factors associated with a good prognosis, this study analyzed the clinical parameters of four patients treated in the department and 109 patients reported in case reports. The median age was 71 years and the median overall survival was 20 months. Patients possessing two independent favorable factors, an elderly status (≥ 70 years) and low serum lactate dehydrogenase (< 500 IU/L) showed a markedly higher 1-year survival than patients lacking either of the two factors in the absence of chemotherapy (94% vs 20%, p = 3 × 10(-5)), which was similarly observed in the chemotherapy group (94% vs 51%, p = 0.002). The use of rituximab was also a strong predictor of survival (89% vs 49%, p = 7 × 10(-6)). Elderly patients not exhibiting an increased lactate dehydrogenase may represent a benign sub-group of effusion lymphoma, which do not require chemotherapy to achieve remission.

Human herpes virus 8-unrelated primary effusion lymphoma-like lymphoma in the pericardium: A case with latency type III Epstein-Barr virus infection showing good prognosis without chemotherapy

Primary effusion lymphoma (PEL) is a rare subtype of non-Hodgkin lymphoma that proliferates in body cavities without detectable masses. PEL is universally associated with human herpes virus-8 (HHV-8) infection and has an aggressive prognosis. Recently, an HHV-8-unrelated PEL-like lymphoma that usually occurs in elderly individuals and follows a more indolent prognosis has been reported, and it is treated as a disease distinct from PEL. However, its pathogenesis and prognostic factors have not been sufficiently clarified. In PEL-like lymphoma accompanied by Epstein-Barr virus (EBV) infection, latent infection types are not mentioned in the literature. Herein, we report the case of an 85-year-old Japanese man with pericardial PEL-like lymphoma who showed good improvement in condition for 24 months after pericardiocentesis without chemotherapy. Serological test results were positive for EBV capsid antigen and EBV nuclear antigen 2 (EBNA2), but negative for human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. The disease phenotype and EBV infection mechanism were immunohistochemically investigated by the cellblock prepared from pericardial effusion. Atypical cells were positive for CD20, CD30, CD45, BCL2, MUM1, EBNA2, latent membrane protein 1, and EBV-encoded RNA (on in situ hybridization), but negative for CD3, CD5, CD10, CD138, cytokeratin AE1/AE3, and HHV-8. Accordingly, this case was considered to be a B-cell activated phenotype with a type III latent EBV infection. Type III latent EBV infection is unusual in PEL.

Human Herpesvirus 8-Negative and Epstein-Barr Virus-Positive Effusion-Based Lymphoma in a Patient with Human Immunodeficiency Virus

A 39-year-old man infected with human immunodeficiency virus (HIV) was admitted to our hospital because of sudden onset of chest pain. Chest radiography revealed pneumothorax of the right lung. Computed tomographic scans disclosed a 5.8-cm-sized emphysematous bulla in the right middle lobe of the lung. Histologically, the wedge-resected lung showed medium to large atypical cells within the bullous cavity of the Pneumocystis jirovecii pneumonia, without solid mass formation. These atypical cells were confirmed to be large B-cell lymphoma, Epstein-Barr virus–positive and human herpesvirus 8–negative. Therefore, this case was not diagnosed as primary effusion lymphoma, but effusion-based lymphoma arising in an emphysematous cavity of an HIV-infected patient. This type of effusion-based lymphoma has never been reported, and, although rare, it should be noted in order to clinically diagnose this lymphoma.

Primary effusion lymphoma in the absence of HIV infection--clinical presentation and management

Primary Effusion Lymphoma (PEL) is a rare type of Non-Hodgkin's Lymphoma caused by human herpesvirus type 8, also termed Kaposi's sarcoma-associated herpesvirus. It usually occurs in human immunodeficiency virus (HIV)-infected patients. A subset of patients is not infected with HIV and their treatment remains poorly defined. To clarify treatment issues in HIV-negative PEL patients, we report on two such patients who represent two opposing ends in the spectrum of treatment and review the literature regarding treatment options and patient outcomes. Either repeated cycles of chemotherapy or, surprisingly, drainage of the malignant effusions alone, proved very effective in our patients. The literature reveals additional treatment options which may be effective including immunochemotherapy, stem cell transplantation, antiviral treatment and immunomodulatory and targeted biological therapy. However, no controlled trials were found due to the rarity of the condition. In the absence of controlled trials, treatment decisions in PEL not associated with HIV must remain individual and patient-tailored.

Establishment and characterization of a novel VEGF-producing HHV-8-unrelated PEL-like lymphoma cell line, OGU1

Primary effusion lymphoma (PEL) is a rare B-cell lymphoma subtype that is characterized by lymphomatous effusion without the presence of masses, and it typically occurs in human immunodeficiency virus (HIV)-infected individuals. Lymphoma cells are universally positive for human herpesvirus 8 (HHV-8). Recently, a cavity-based effusion lymphoma that is similar to PEL without HHV-8 infection, called HHV-8-unrelated PEL-like lymphoma, has been reported in non-HIV-infected individuals. However, the pathophysiology of this lymphoma is largely undefined. We established a novel B-cell line OGU1 derived from a patient with HHV-8-unrelated PEL-like lymphoma. Notably, OGU1 cells produced vascular endothelial growth factor (VEGF) and expressed VEGF receptor 1, whose inhibitors retarded cell growth. Because VEGF acts as a vascular permeability and growth factor, it could play a role, at least in part, in the pathogenesis of this unique lymphoma. Thus, the OGU1 cell line is useful for the investigation of HHV-8-unrelated PEL-like lymphoma.

HHV8-negative effusion based lymphoma: a series of 17 cases at a single institution

INTRODUCTION

Human herpesvirus 8-positive (HHV8+) primary effusion lymphoma is a well-recognized clinicopathologic entity. In contrast, HHV8-negative (HHV8-) effusion-based lymphoma (EBL) is incompletely characterized and under-recognized. We describe 17 cases of HHV8- EBL at our institution.

MATERIALS AND METHODS

Cytology and available immunohistochemistry and cytogenetics were reviewed. Patient demographics, history, and outcome were obtained from medical records.

RESULTS

The effusions were pleural (n = 9; 53%), peritoneal (n = 4; 24%), pericardial (n = 3; 18%), and pleural and pericardial (n = 1; 6%). Fifteen cases (88%) were CD20+ and 15 had sufficient information for classification by Hans algorithm (CD10, BCL6, MUM1): 11 (73%) nongerminal center and 4 (27%) germinal center phenotype. Epstein-Barr virus in situ hybridization was negative in 16 cases (94%). Three of 14 cases were MYC+ by immunohistochemistry. Fluorescence in situ hybridization, performed on 5 of the 17 cases, showed a MYC rearrangement in 1 case and a BCL6 rearrangement in 2 cases. Most patients were elderly (median age 86 years) and female (82%). Human immunodeficiency virus testing results, available in 4 patients, were negative. Seven (41%), including 1 of 2 heart transplant recipients, had congestive heart failure. Follow-up (5 days to 12 years) was available for 16 patients including 4 who survived ≥8 years. Only 1 of the 8 known deaths was clinically attributed to lymphoma.

CONCLUSIONS

HHV8- lymphomas that occur in body cavity effusions without detectable lymphomatous masses are usually composed of large CD20+ lymphoid or lymphoplasmacytoid cells. In contrast to HHV8+ primary effusion lymphoma, patients with HHV8- EBL are usually elderly, lack a documented human immunodeficiency virus-positive history, and have a longer disease specific survival.

Current status of treatment for primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell non-Hodgkin's lymphoma that usually presents with malignant effusions without tumor masses. An extracavitary or solid variant of PEL has also been described. Human herpes virus 8/Kaposi sarcoma-associated herpes virus (HHV-8/KSHV) is universally associated with the pathogenesis of PEL. More than 70% of cases occur with concurrent Epstein-Barr virus infection, but its relation to the pathogenesis is unknown. Patients are found in the context of immunosuppressive states (HIV-1 infection, post-organ transplantation). PEL is usually treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like chemotherapy with antiretroviral therapy if HIV-1 is positive. However, it is generally resistant to chemotherapy with a short median survival of less than 6 months. The optimal treatment for PEL has not been established yet. More intensive chemotherapy, such as dose-adjusted EPOCH (DA-EPOCH; etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) and CDE (cyclophosphamide, doxorubicin, etoposide) are expected to show a favorable prognosis. Recently, the molecular steps in KSHV/HHV-8-driven oncogenesis have begun to be revealed, and molecular targeting therapies such as proteasome, NF-κB, cytokines and surface antigens would provide evidence for their clinical use.

Primary effusion lymphoma with aberrant T-cell phenotype in an iatrogenically immunosuppressed renal transplant male: cytologic diagnosis in peritoneal fluid

Primary effusion lymphoma (PEL) is an unusual class of non-Hodgkin's lymphoma that develops in body cavities, without associated mass lesions. It has been linked to human herpes virus 8 (HHV-8), an etiological factor of Kaposi's sarcoma. Although PEL is a B-cell lymphoma, the neoplastic cells are usually of the "null" phenotype by immunocytochemistry. The relative infrequency of this entity, the absence of wide casuistic allowing a better characterization, and its unfavorable outcome, strongly support the need of a deeper knowledge. We report the clinico-biological findings of a 49-year-old male who was iatrogenically suppressed patient for 29 years because of renal transplantation. This case was diagnosed cytologically as peritoneal PEL and confirmed histologically on peritoneal biopsies. The immune status for both HHV-8 and Epstein-Barr virus (EBV) was evaluated and showed positive immunostaining only for the former. The combination of the immunocytochemistry results with the existence of a clonal rearrangement in the immunoglobulin heavy chain gene (identified by PCR) was compatible with the diagnosis of PEL. The presence of T-cell markers was consistent with the diagnosis of PEL with an aberrant T-cell phenotype.