Primary Effusion Lymphoma

Background

This is a rare but fascinating lymphoma that arises in body cavities such as the peritoneum. It is associated with infection by Human Herpes Virus 8, the same viral etiologic agent of Kaposi's sarcoma. Studies have convincingly found that these are variants of a B-cell lymphoma.

Outline

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Special Stains/Immunohistochemistry/Electron Microscopy
Differential Diagnosis
Prognosis and Treatment
Commonly Used Terms
Internet Links

EPIDEMIOLOGY CHARACTERIZATION

SYNONYMS Body cavity lymphoma
AIDS associated body cavity lymphoma

INCIDENCE Rare

DISEASE ASSOCIATIONS CHARACTERIZATION

TRANSPLANTATION

Primary effusion lymphoma after heart transplantation: a new entity associated with human herpesvirus-8.

Dotti G, Fiocchi R, Motta T, Facchinetti B, Chiodini B, Borleri GM, Gavazzeni G, Barbui T, Rambaldi A.

Divisione di Ematologia, Ospedali Riuniti di Bergamo, Italy.

Leukemia 1999 May;13(5):664-70 Abstract quote

Deep immunosuppression and Epstein-Barr virus (EBV) infection promote the emergence of lymphoproliferative disorders in patients undergoing solid organ transplantation. In the last few years a new herpesvirus, named human herpesvirus-8 (HHV-8), has been identified in Kaposi's sarcoma and primary effusion lymphoma (PEL) developing in AIDS patients. Subsequently, the same viral DNA sequences have been identified in almost all cases of Kaposi's sarcoma emerged outside HIV infection, thus suggesting their possible pathogenetic role in this tumor. Similarly, the association between HHV-8 and PEL also emerged in cases without HIV infection, even though the total number of these patients is still limited.

Here, we focus on the emergence of this unusual lymphoma in patients undergoing solid organ transplant and underline once again its association with the HHV-8. Moreover, despite the characteristic local growth of this peculiar type of lymphoma, we demonstrate at the molecular level, an early neoplastic spread to the bone marrow suggesting the need to investigate in more detail the origin of the disease, as well as the molecular mechanisms controlling its systemic dissemination.

HIV

Primary effusion lymphoma with herpesvirus 8 DNA in patients coinfected with HIV and hepatitis C virus: a report of 2 cases.

Hong S, Krafft AE.

Department of Pathology, College of Medicine, Howard University Hospital, Washington, DC, USA.

AIDS Read 2001 Aug;11(8):418-22 Abstract quote

The primary effusion lymphoma (PEL), commonly described in patients with AIDS, is a unique subset of diffuse large cell lymphoma in which the malignant lymphocytes proliferate exclusively in serous cavities.

The cytologic, immunophenotypic, and molecular features of PEL are presented from findings of 2 patients coinfected with HIV and hepatitis C virus who presented with abdominal pain. Abdominal radiography in both patients displayed marked peritoneal effusions. Cytomorphologic examination of peritoneal fluid revealed a malignant lymphoma in both. Their immunophenotypic expression was CD30 (Ki-1) and epithelial membrane antigen. Molecular analysis demonstrated human herpesvirus 8 DNA in both patients and bcl-2 oncogene rearrangement within the major breakpoint region of t(14;18) chromosome translocation in Case B only.

Clinical correlation supports the current concept that PEL represents a primary HIV/AIDS-related lymphoma in effusion. Cytomorphologic examination of body cavity fluid serves as a tool for the initial diagnosis of PEL.

CASTLEMAN'S DISEASE

Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease.

Ascoli V, Signoretti S, Onetti-Muda A, Pescarmona E, Della-Rocca C, Nardi F, Mastroianni CM, Gastaldi R, Pistilli A, Gaidano G, Carbone A, Lo-Coco F.

Anatomia Patologica, Dipartimento di Medicina Sperimentale e Patologia, Universita La Sapienza, Roma, Italy.

J Pathol 2001 Feb;193(2):200-9 Abstract quote

Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL.

This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders.

Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

PATHOGENESIS CHARACTERIZATION

HHV-8

Genetic characterization of HHV-8/KSHV-positive primary effusion lymphoma reveals frequent mutations of BCL6: implications for disease pathogenesis and histogenesis.

Gaidano G, Capello D, Cilia AM, Gloghini A, Perin T, Quattrone S, Migliazza A, Lo Coco F, Saglio G, Ascoli V, Carbone A.

Department of Medical Sciences, University of Torino at Novara, Italy.

Genes Chromosomes Cancer 1999 Jan;24(1):16-23 Abstract quote

Human herpesvirus-8/Kaposi sarcoma-associated herpesvirus-positive primary effusion lymphoma (PEL) is a recently identified B-cell non-Hodgkin lymphoma category characterized by liquid growth in the serous body cavities. Apart from viral infection, no genetic alteration is known to be associated with PEL and no recurrent cytogenetic abnormality has been identified in these lymphomas. Yet the consistent monoclonality of PEL indicates that the disease is not solely a virus-driven proliferation.

Here we report that PEL is associated with a high frequency of mutations of BCL6 5' noncoding regions, and we identify karyotypic abnormalities that may be recurrently involved in these lymphomas. Mutations of BCL-6 5' noncoding regions occurred in 8/13 PEL. Mutations occurred in the absence of BCL6 gross rearrangements were often multiple in the same patient (7/8 mutated cases), and occurred in both HIV-positive and HIV-negative individuals.

Since BCL6 mutations are regarded as a genetic marker of B-cell transition through the germinal center (GC), these data are consistent with histogenetic derivation of PEL from GC or post-GC B-cells. Cytogenetic and FISH analysis of seven PEL cell lines showed frequent occurrence of complete or partial trisomy 12 (7/7 cases), trisomy 7 (4/7 cases), and abnormalities of bands Iq21-25 (5/7 cases).

Differential viral protein expression in Kaposi's sarcoma-associated herpesvirus-infected diseases: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease.

Parravicini C, Chandran B, Corbellino M, Berti E, Paulli M, Moore PS, Chang Y.

Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.

Am J Pathol 2000 Mar;156(3):743-9 Abstract quote

Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is linked to KS, primary effusion lymphomas (PEL), and a subset of multicentric Castleman's disease (MCD). Transcript mapping studies using PEL cell lines have allowed preliminary classification of viral gene expression into constitutive (class I) and inducible (class II/III) categories.

To determine whether viral gene expression differs in vivo, we examined tissue sections of KSHV-infected disorders, using specific antibodies against proteins that are representative of the different expression classes of KSHV genes. ORF73/LANA appears to be a surrogate marker for KSHV infection because it is constitutively expressed in vitro and in vivo in all KSHV-infected cells. Expression of vIRF1, vIL6, and PF-8 proteins in the infected B cells of MCD lymph nodes reproduces the expression pattern observed in TPA-stimulated KSHV-infected B-cell lines.

In contrast, the protein expression of the inducible viral genes that we tested in KS and PEL biopsies is restricted to PF-8 and vIL6, respectively. The tightly restricted expression of KSHV proteins in vivo differs from the dysregulated expression of inducible KSHV genes in vitro and suggests that viral gene expression in KSHV-infected cell lines does not accurately reflect what occurs in diseased tissues.

These differences may be related to either cell-specific or immune restriction of viral replication.

The tyrosine kinase receptor met and its ligand HGF are co-expressed and functionally active in HHV-8 positive primary effusion lymphoma.

Capello D, Gaidano G, Gallicchio M, Gloghini A, Medico E, Vivenza D, Buonaiuto D, Fassone L, Avanzi GC, Saglio G, Prat M, Carbone A.

Division of Internal Medicine, Department of Medical Sciences, Amedeo Avogadro University of Eastern Piedmont, Novara, Italy.

Leukemia 2000 Feb;14(2):285-91 Abstract quote

Primary effusion lymphoma (PEL) harbors consistent infection by human herpesvirus-8, preferentially develops in immunodeficient patients and selectively localizes to the serous body cavities. Histogenetic analysis has suggested that PEL originates from post-germinal center, pre-terminally differentiated B cells sharing phenotypic features with plasma cells.

Here we have investigated the expression status and functional integrity of the Met tyrosine kinase receptor and of its ligand hepatocyte growth factor (HGF). Thirteen PEL (nine cell lines and four primary specimens) were analyzed for Met and HGF expression and function by multiple assays. For comparison, a panel of 34 high grade B cell non-Hodgkin lymphomas (NHL) other than PEL was also investigated. Co-expression of Met and HGF was found in all PEL analyzed, whereas it was restricted to 1/34 B cell NHL other than PEL (P < 0.001; chi2 test). The Met protein expressed by PEL displays biochemical characteristics typical of Met expressed by other cell types and is capable of tyrosine autophosphorylation. By using a combination of immunological and biological assays, production and secretion of a functional HGF species was identified in all PEL cell lines analyzed. HGF stimulation of PEL cells rapidly induces Met tyrosine phosphorylation, demonstrating the functional integrity of the Met/HGF loop. Because of the well known mitogenic and motogenic properties of Met/HGF interactions, these data may bear implications for PEL growth and dissemination.

Among B cell neoplasms, Met/HGF co-expression selectively clusters with PEL and, as demonstrated by previous studies, with multiple myeloma plasma cells, thus reinforcing the notion that PEL displays biologic similarities with tumors derived from late stages of B cell differentiation.

Expression of MUM1/IRF4 selectively clusters with primary effusion lymphoma among lymphomatous effusions: implications for disease histogenesis and pathogenesis.

Carbone A, Gloghini A, Cozzi MR, Capello D, Steffan A, Monini P, De Marco L, Gaidano G.

Division of Pathology, Centro di Riferimento Oncologico, IRCCS, Istituto Nazionale Tumori, Aviano, Italy.

Br J Haematol 2000 Oct;111(1):247-57 Abstract quote

Primary effusion lymphoma (PEL) is a peculiar B-cell lymphoma characterized by infection by human herpesvirus type-8/Kaposi sarcoma-associated herpesvirus (HHV-8/KSHV) and by preferential growth in the serous body cavities. Histogenetic studies have suggested that PEL originates from B cells at a late stage of differentiation.

n this study, we have investigated PEL for the expression status of MUM1/IRF4 (multiple myeloma 1/interferon regulatory factor 4) protein, which is involved in physiological B-cell maturation and represents a histogenetic marker of late B-cell differentiation. Using multiple detection assays, all cases of PEL (n = 22) were found to express MUM1/IRF4 molecules. MUM1/IRF4 expression was a selective feature of PEL among lymphomas involving the serous body cavities as secondary lymphomatous effusions generally failed to express the protein. In reactive lymphoid tissues, MUM1/ IRF4 expression clustered with advanced stages of B-cell differentiation. Comparison of MUM1/IRF4 expression with that of other histogenetic markers defined two phenotypic variants of PEL, i.e. MUM1/IRF4+, CD138/syndecan-1+, B-cell antigen- (20 out of 22 cases) and MUM1/IRF4+, CD138/syndecan-1-, B-cell antigen+ (2 out of 22 cases), suggesting a certain degree of heterogeneity in the disease histogenesis.

The implications of these data are threefold. First, MUM1/IRF4 expression corroborates the notion that PEL originates from post-germinal centre, preterminally differentiated B-cells. Second, MUM1/IRF4 may help in the differential diagnosis of PEL among other lymphomas involving the serous body cavities. Finally, MUM1/IRF4 may interact with HHV-8/KSHV-encoded interferon regulatory factors (IRFs) and thus contribute to PEL escape from interferon-mediated control of viral infection.

Molecular characterization of HHV-8 positive primary effusion lymphoma reveals pathogenetic and histogenetic features of the disease.

Gaidano G, Capello D, Fassone L, Gloghini A, Cilia AM, Ariatti C, Buonaiuto D, Vivenza D, Gallicchio M, Avanzi GC, Prat M, Carbone A.

Division of Internal Medicine, Department of Medical Sciences, Amedeo Avogadro University of Eastern Piedmont, Via Solaroli 17, 28100, Novara, Italy.

J Clin Virol 2000 May;16(3):215-24 Abstract quote

BACKGROUND: Primary effusion lymphoma (PEL) associates with HHV-8 infection, preferentially develops in immunodeficient patients and grows in the serous body cavities. PEL derives from post-germinal center, pre-terminally differentiated B-cells. The pathogenesis of PEL is unclear and the sole identified genetic lesions are human herpesvirus type-8 (HHV-8) infection in all cases and EBV infection in 70% of cases. Epstein-Barr virus (EBV) infection in PEL displays a latency I phenotype.

OBJECTIVES: To clarify the pathogenesis and histogenesis of PEL by investigating (1) the lymphoma karyotype; (2) the expression status of the Met tyrosine kinase receptor and of its ligand hepatocyte growth factor (HGF); (3) the molecular profile of EBV, with particular focus on mutations of EBNA-1 genes, which are thought to affect viral tumorigenicity in EBV-infected neoplasms displaying the latency I phenotype.

STUDY DESIGN: Twenty-four PEL (nine cell lines and 15 primary specimens) formed the basis of the study. Karyotypes were investigated by conventional cytogenetics and fluorescent in situ hybridization (FISH) in selected cases. The expression status of Met and HGF was defined by multiple techniques, including RT-PCR, FACS analysis, immunocytochemistry, Western blot studies and ELISA. The molecular profile of EBNA-1 genes of EBV were investigated by DNA direct sequencing.

RESULTS: Trisomy 7, trisomy 12 and breaks at 1q21-q25 are recurrently associated with PEL. PEL consistently co-express Met and HGF both at the mRNA and protein level. Among aggressive B-cell lymphomas, Met/HGF co-expression appears to be relatively specific for PEL. The EBNA-1 gene of EBV displays a high degree of genetic heterogeneity in PEL, with no preferential association with one specific variant.

CONCLUSIONS: PEL associates with recurrent chromosomal alterations, suggesting that viral infection is not sufficient for tumor development and that lesions of cellular genes may be required. The expression of Met/HGF by PEL cells may bear implications for the lymphoma proliferation and growth pattern, since Met/HGF interactions influence cell mitogenesis and motogenesis. EBV infection in PEL displays a latency I phenotype and fails to associate with specific EBNA-1 variants, suggesting that the role of EBV in PEL is not mediated by the major transforming pathways currently known in EBV positive lymphomas.

Proliferation in HHV-8-positive primary effusion lymphomas is associated with expression of HHV-8 cyclin but independent of p27(kip1).

Carbone A, Gloghini A, Bontempo D, Monini P, Tirelli U, Volpe R, Browning PJ, Gaidano G.

Division of Pathology, Centro di Riferimento Oncologico, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Nazionale Tumori, Aviano, Italy.

Am J Pathol 2000 Apr;156(4):1209-15 Abstract quote

Primary effusion lymphoma (PEL) develops in immunodeficient patients, selectively localizes to the serous body cavities, and harbors infection by human herpesvirus type-8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus. HHV-8 encodes a viral (v)-cyclin homologous to cellular D-type cyclins, a class of positive cell-cycle regulators that are physiologically modulated by the p27(Kip1) cell cycle inhibitor.

The aims of the present study were: 1) to establish the expression pattern of p27(Kip1) in PEL; and 2) to address the relationship between p27(Kip1) expression, proliferation index, and expression of cellular cyclin D1 and v-cyclin in PEL. Expression of p27(Kip1) was detected in all (n = 18) PEL samples analyzed by both immunocytochemistry and Western blot. All PELs displayed a high proliferation index as assessed by Ki-67 staining. Expression of cellular cyclin D1 was absent in all PELs tested, which conversely expressed (14 out of 14 samples) v-cyclin by immunocytochemistry and/or Western blot. In contrast to PELs, HHV-8-negative lymphomatous effusions secondary to a tissue-based lymphoma generally failed to express p27(Kip1). Overall, these data show that PELs consistently express p27(Kip1) protein despite the high proliferative rate of the lymphoma clone, suggesting that p27(Kip1) may be unable to drive cell-cycle arrest in PEL cells.

The co-existence of p27(Kip1) expression and high proliferative index is a selective feature of PEL among lymphomas involving the serous body cavities, because lymphomatous effusions secondary to a tissue-based lymphoma generally display the inverse relationship between p27(Kip1) positivity and growth fraction observed in normal lymphoid tissues and in most other lymphomas. Expression of p27(Kip1) in PEL associates with expression of HHV-8 v-cyclin, but not of cellular cyclin D1. The fact that HHV-8 v-cyclin is resistant to p27(Kip1)-modulated inhibition, whereas cellular cyclin D1 is sensitive, may explain, at least in part, the co-existence of p27(Kip1) expression and high proliferative index observed in PEL.

LABORATORY/RADIOLOGIC/
OTHER TESTS
CHARACTERIZATION

RADIOLOGIC

LABORATORY MARKERS

PCR

Primary effusion lymphoma: cytopathologic diagnosis using in situ molecular genetic analysis for human herpesvirus 8.

Wakely Jr PE Jr, Menezes G, Nuovo GJ.

Department of Pathology, The Ohio State University, Columbus, Ohio.

Mod Pathol 2002 Sep;15(9):944-50 Abstract quote
Primary effusion lymphoma is a form of diffuse large B-cell lymphoma with neoplastic cells largely limited to proliferation within major body cavities. Human herpes virus-8 is both integral to and required for an unequivocal diagnosis of primary effusion lymphoma. Prior methods for virus identification include DNA extraction with Southern blot analysis or in situ hybridization from paraffin-embedded samples.

Our aim is to examine the utility of human herpesvirus-8 identification performed directly on smears from effusion samples by reverse transcriptase in situ polymerase chain reaction in patients with primary effusion lymphoma. Smears and cell block of body cavity fluids from five patients with effusions (three pleural, one peritoneal, and one both pleural and peritoneal) were examined microscopically by conventional Papanicolaou and Romanowsky (Diff-Quik) staining, and by reverse transcriptase in situ polymerase chain reaction for human herpesvirus-8 detection. In situ hybridization was performed also for Epstein-Barr virus (EBER-1, -2), T-cell receptor-beta, and kappa (kappa) and lambda (lambda) mRNA in all cases. Five adults ranged from 40-81 years of age. Three adults were HIV positive, one was a renal transplant recipient, and the oldest patient (Case 3) had the unusual distinction of a normal immune status. Two of three HIV-seropositive patients had concurrent Kaposi sarcoma. All samples were cytologically similar with lymphocytes having large-cell, plasmablastic, and immunoblastic morphology. Malignant cells from effusions were as follows: human herpesvirus-8 positive (all five cases), exhibited kappa monoclonal light chain (five cases), Epstein-Barr virus positive (three cases), and T-cell beta-gene receptor positive (two cases). Diffuse large B-cell lymphoma was evident in one peritoneal nodule (<10% human herpesvirus-8 positive cells in contrast to >90% positive in effusions, all kappa positive). Six other tissue specimens (lung, bone marrow, spleen, lymph node) were human herpesvirus-8 negative, and showed no evidence of lymphoma.

Reverse transcriptase in situ polymerase chain reaction demonstrated near-complete restriction of human herpesvirus-8-infected malignant lymphoid cells to those in body cavities. Definitive diagnosis of primary effusion lymphoma is possible directly from cytologic smears/cell block by combining cytologic morphology with reverse transcriptase in situ polymerase chain reaction detection of human herpesvirus-8.

VIRAL LOAD

Detection rate and intratumoral virus load of human herpesvirus-8 in immunodeficiency-related B-cell lymphoid malignancies.

Feuillard J, Aubin JT, Poirel L, Davi F, Kujas M, Rousselet MC, Angonin R, Raphael M, Agut H.

Service d'Hematologie Biologique, Centre Hospitalier Avicenne, Bobigny, France.

J Med Virol 1997 Nov;53(3):277-81 Abstract quote

Human herpesvirus-8 (HHV-8), associated with Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease, has been found in circulating B-cells and might have a causative role in B-cell malignancies associated with immunodeficiency syndromes.

We determined the rate of detection and intratumoral virus load of HHV-8 by means of a semiquantitative approach in post-transplant lymphoproliferative diseases (PTLDs), AIDS-related non-Hodgkin's lymphomas (NHLs), including both Burkitt's lymphomas (BLs) and large cell lymphomas (LCLs), as well as in control groups consisting of follicular hyperplasias (FHs) and HIV-negative LCLs. HHV-8 sequences were detected at a similar rate in HIV-negative PTLDs (24%), HIV-negative LCLs (22%) and HIV-negative FHs (17%). The detection rate was significantly higher in HIV-positive BLs (73%), HIV-positive LCLs (67%), and HIV-positive FHs (65%) supporting the view of an epidemiological link between HHV-8 and HIV infections. The viral load was 10(2) genome copies per cell in the single case of primary effusion lymphoma included in the LCL group while it was 10(-3) copy per cell (median value; range: 10(-4)-10(-1)) in all the other HHV-8-positive samples. No significant difference of viral load was found according to HIV status.

The virus loads of PTLDs and HIV-positive LCLs were significantly higher than those observed in HIV-positive BLs and FHs, suggesting, to some extent, that the degree of immunodeficiency may influence HHV-8 replication. However, with the exception of the single case of primary effusion lymphoma studied, the low intratumoral load of HHV-8 strongly argues against a direct causative agent of the virus in the occurrence of PTLDs and AIDS-related NHLs.

GROSS APPEARANCE/
CLINICAL VARIANTS CHARACTERIZATION

GENERAL

VARIANTS

SMALL BOWEL MASS

Primary Effusion Lymphoma With Subsequent Development of a Small Bowel Mass in an HIV-Seropositive Patient: A Case Report and Literature Review.

Huang Q, Chang KL, Gaal K, Arber DA.
Am J Surg Pathol 2002 Oct;26(10):1363-7 Abstract quote
Primary effusion lymphoma is a distinct clinicopathologic entity usually characterized by presentation as a lymphomatous body cavity effusion in the absence of a solid tumor mass or dissemination during its clinical course. This lymphoma is typically present in human immunodeficiency virus (HIV)-infected patients and frequently associated with Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV8) viral sequences.

Here we report a rare case of KSHV/HHV8-associated primary effusion lymphoma with secondary involvement of the small bowel as an obstructive tumor mass in an HIV-infected man.

The solid small bowel lymphoma demonstrated essentially identical morphology, immunophenotype, KSHV/HHV8 viral status, and immunoglobulin light chain rearrangements to the pleural cavity-based primary effusion lymphoma in the same patient.

SUBARACHNOID SPACE

Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma arising in the subarachnoid space.

Ely SA, Powers J, Lewis D, Chang S, Rubio A, O'Leary J, Knowles DM.

Department of Pathology, The Weill Medical College and Graduate School of Medical Sciences of Cornell University/New York Presbyterian Hospital, New York, USA.

Hum Pathol 1999 Aug;30(8):981-4 Abstract quote

Primary effusion lymphoma (PEL) is a rare and distinctive type of B-cell non-Hodgkin's lymphoma (NHL) that occurs primarily, although not exclusively, in patients with AIDS. It usually develops as a lymphomatous effusion in the absence of a tumor mass, characteristically contains the Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8), usually also contains the Epstein-Barr virus (EBV), displays a characteristic cytomorphology bridging immunoblastic and anaplastic large cell lymphoma, often expresses an indeterminate immunophenotype, and a B-cell genotype. Thus far, PEL has been limited almost entirely to the pleural, peritoneal, and pericardial cavities.

We describe a NHL occurring in a gay man with AIDS that is typical of PEL in that it arose in a body cavity or space without an associated tumor mass, displays the cytomorphology typical of PEL, is a clonal B-cell neoplasm, and contains KSHV as well as EBV.

This case is singularly distinctive in that it is the first case of PEL reported to arise in the subarachnoid space. This unique case further supports the strong association between KSHV and malignant lymphoma arising in body cavities and growing as an effusion.

HISTOLOGICAL TYPES CHARACTERIZATION

GENERAL

Primary effusion lymphoma: a liquid phase lymphoma of fluid-filled body cavities.

Gaidano G, Carbone A.

Division of Internal Medicine, Department of Medical Sciences, Amedeo Avogadro University of Eastern Piedmont, Italy.

Adv Cancer Res 2001;80:115-46 Abstract quote

Primary effusion lymphoma (PEL) is a B-cell neoplasm characterized by infection of the tumor clone by human herpesvirus type-8/Kaposi's sarcoma-associated herpesvirus (HHV-8/KSHV) and by liquid growth in fluid-filled body spaces. During its entire clinical course, the lymphoma tends to remain localized to the serous body cavities with no formation of solid tumor masses.

The epidemiology of PEL points to a close link with underlying immunodeficiency of the host, as most cases develop in individuals severely immunocompromised because of preexisting acquired immunodeficiency syndrome. The histogenesis and pathogenesis of PEL have been clarified to a sizeable extent by intensive investigations performed since the disease recognition in 1995.

PEL is composed of postgerminal center B cells, which bridge immunoblastic and anaplastic features and typically display a non-B, non-T phenotype consistent with late stages of B-cell differentiation. HHV-8/KSHV is thought to play a major role in PEL pathogenesis via expression of several viral latent genes, which have the potential to affect B-cell growth.

Other factors involved in PEL pathogenesis include deregulation of cytokine and growth factor autocrine loops, molecular alterations of the tumor DNA, cell cycle abnormalities, stimulation and selection by antigen, and infection by Epstein-Barr virus, which occurs in 70% of PEL cases.

In the years since the disease discovery, the distinctiveness of the biological and clinicopathological features of PEL has prompted its recognition as an independent lymphoma category by the World Health Organization classification system of hematologic neoplasms.

VARIANTS

Early peripheral lymph node involvement of human herpesvirus 8-associated, body cavity-based lymphoma in a human immunodeficiency virus-negative patient.

Ariad S, Benharroch D, Lupu L, Davidovici B, Dupin N, Boshoff C.

Department of Oncology, Soroka Medical Center and Ben Gurion University of the Negev, Beer Sheva, Israel.

Arch Pathol Lab Med 2000 May;124(5):753-5 Abstract quote

Human herpesvirus 8 (HHV-8), or Kaposi sarcoma-associated herpesvirus, is a gamma herpesvirus first detected in a specimen of Kaposi sarcoma from a human immunodeficiency virus (HIV)-positive patient. Human herpesvirus 8 is also found in an unusual clinicopathologic form of body cavity-based B-cell lymphoma, which has been named primary effusion lymphoma (PEL) and occurs primarily in HIV-positive patients. PEL is characterized by the formation of lymphomatous effusions, without obvious lymphadenopathy, tumor masses, or bone marrow involvement. Only a few cases of PEL in HIV-seronegative patients have been reported.

We describe a case of an HHV-8-associated lymphoma, with ascites, pleural effusion, and axillary lymphadenopathy in an HIV-negative patient. The patient was a 68-year-old Jewish man of North African extraction, with a previous history of coronary bypass surgery and multiple blood transfusions. The pleural fluid contained large atypical lymphoid cells and was suggestive of lymphoma but could not provide a conclusive diagnosis of PEL. The lymph node contained groups of large anaplastic lymphoid cells. Polymerase chain reaction for HHV-8 performed on the lymph node specimen was positive, establishing the diagnosis of PEL. Polymerase chain reaction for Epstein-Barr virus was negative. Results of a gallium scan were normal. The patient did not respond to combination chemotherapy with cyclophosphamide, doxorubicin, vincristine sulfate, and prednisone and progressively developed, massive intra-abdominal solid tumor formation.

To our knowledge, this is the first report of a case of PEL that demonstrates peripheral lymph node involvement at diagnosis and the first report of PEL in an Israeli patient.

Association of primary pleural effusion lymphoma of T-cell origin and human herpesvirus 8 in a human immunodeficiency virus-seronegative man.

Lechapt-Zalcman E, Challine D, Delfau-Larue MH, Haioun C, Desvaux D, Gaulard P.

Departement de Pathologie Hopital Henri Mondor, Creteil, France.

Arch Pathol Lab Med 2001 Sep;125(9):1246-8 Abstract quote

We describe a case of an 87-year-old human immunodeficiency virus (HIV)-negative man who developed a primary pleural lymphoma without any identifiable tumor mass associated with human herpesvirus 8 (HHV-8) infection.

A large T-cell lymphoma was diagnosed based on morphologic, immunophenotypic, and molecular findings. The HHV-8 DNA sequences were detected using specific polymerase chain reaction amplification in the lymphomatous effusion. Study of the patient's serum confirmed the HHV-8 infection. This case report displays the characteristic features of HHV-8-related body cavity-based lymphoma/primary effusion lymphoma previously reported in HIV-seronegative patients, except that it is of T-cell origin.

Whether this case may be included or not within the primary effusion lymphoma entity, the association of a pleural T-cell non-Hodgkin lymphoma with HHV-8 infection raises the question of the possible occurrence of T cells as the target of malignant transformation associated with HHV-8 infection.

HHV8-negative primary effusion lymphoma of the peritoneal cavity presenting with a distinct immunohistochemical phenotype.

Tanaka S, Katano H, Tsukamoto K, Jin M, Oikawa S, Nishihara H, Sawa H, Sawada K, Shimizu M, Sata T, Fujioka Y, Nagashima K.

Laboratory of Molecular and Cellular Pathology,Second Department of Internal Medicine II, Kyorin University School of Medicine, Tokyo, Japan.

Pathol Int 2001 Apr;51(4):293-300 Abstract quote

Primary effusion lymphoma (PEL) has been recognized as a body-cavity-based lymphoma that was originally reported to be associated with human herpes virus 8 (HHV8) infection, and was frequently found in human immunodeficiency virus-positive (HIV) patients.

Here we describe an autopsy case of PEL of the peritoneal cavity in an immunocompetent patient. Cytological analysis of tumor cells within ascites revealed immunocytochemical features of keratin positivity and CD45 negativity. At autopsy, the presence of a massive volume of ascites as well as diffuse tumor cell infiltrates within the serosa of the intestine and mesenterium were observed. Tumor cells were morphologically similar to anaplastic large-cell lymphoma, but were immunohistochemically positive for keratin and epithelial membrane antigen (EMA). They also showed no reactivity to representative lymphocyte surface markers including CD45, in addition to being negative for CD30 and p80NPM/ALK. Molecular analysis of the tumor cells revealed monoclonality of the immunoglobulin heavy-chain gene rearrangement which demonstrated a lymphoma of the B-cell lineage.

Furthermore, HHV8 was not detected by immunohistochemical analysis, PCR or nested PCR technique. Based on these results, we consider the present case to be an HHV8-negative PEL with keratin and EMA positivity.

SPECIAL STAINS/IMMUNOPEROXIDASE/
OTHER CHARACTERIZATION

SPECIAL STAINS

IMMUNOPEROXIDASE

Association of Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma with expression of the CD138/syndecan-1 antigen.

Gaidano G, Gloghini A, Gattei V, Rossi MF, Cilia AM, Godeas C, Degan M, Perin T, Canzonieri V, Aldinucci D, Saglio G, Carbone A, Pinto A.

Division of Internal Medicine, Department of Medical Sciences, University of Torino at Novara, Novara, Italy.

Blood 1997 Dec 15;90(12):4894-900 Abstract quote

Primary effusion lymphoma (PEL) represents a novel B-cell non-Hodgkin's lymphoma (NHL) type associated with Kaposi's sarcoma-associated herpesvirus infection and typically growing as lymphomatous effusions in the body cavities. The precise B-cell subset from which PEL originates as well as the biologic mechanisms responsible for its peculiar growth pattern are unclear.

In this study, we have analyzed PEL for the expression status of CD138/syndecan-1, a molecule selectively associated with late stages of B-cell differentiation and implicated in cell-to-cell and cell-to-extracellular matrix interactions. PEL patient samples (n = 7) and cell lines (n = 5) were investigated by multiple approaches, including immunocytochemistry, flow cytometry, RNA analysis, and Western blot studies. For comparison, lymphomatous effusions other than PEL (n = 13) and tissue-based NHL (n = 103) were also tested. Expression of CD138/syndecan-1 associates at high frequency with PEL (5 of 7 patient samples and 5 of 5 cell lines), whereas it is consistently absent among other lymphomatous effusions (n = 13).

The CD138/syndecan-1 isoform expressed by PEL has an average molecular weight of 420 kD, which is substantially different from that of CD138/syndecan-1 molecules generally expressed by plasma cells. These data, along with previous immunophenotypic evidence, unequivocally define that PEL cells represent a preterminal stage of B-cell differentiation and may bear implications for the peculiar growth pattern of this lymphoma.

Distribution of human herpesvirus-8 latently infected cells in Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma.

Dupin N, Fisher C, Kellam P, Ariad S, Tulliez M, Franck N, van Marck E, Salmon D, Gorin I, Escande JP, Weiss RA, Alitalo K, Boshoff C.

Departments of Oncology and Molecular Pathology, Royal Free and University College Medical School, UCL, London, United Kingdom W1P 6BT.

Proc Natl Acad Sci U S A 1999 Apr 13;96(8):4546-51 Abstract quote

Human herpesvirus 8 (HHV-8, also called KSHV) is linked to the etiopathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). The universal presence of HHV-8 in early KS has not yet been shown.

We used a mAb (LN53) against latent nuclear antigen-1 (LNA-1) of HHV-8 encoded by ORF73 to study the distribution of the cell types latently infected by HHV-8 in patch, plaque, and nodular KS, MCD, and PEL. In early KS, HHV-8 is present in <10% of cells forming the walls of ectatic vessels. In nodular KS, HHV-8 is present in cells surrounding slit-like vessels and in >90% of spindle cells, but not in normal vascular endothelium. In addition, HHV-8 colocalizes with vascular endothelial growth factor receptor-3 (VEGFR-3), a marker of lymphatic and precursor endothelium.

In early KS lesions, VEGFR-3 is more extensively expressed than LNA-1, indicating that HHV-8 is not inducing the proliferation of VEGFR-3-positive endothelium directly. In MCD, HHV-8 is present in mantle zone large immunoblastic B cells. No staining for LNA-1 is seen in samples from multiple myeloma, prostate cancer, and angiosarcoma, supporting the absence of any etiological link between these diseases and HHV-8.

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES

CD138-positive and Kaposi's sarcoma-associated herpesvirus (KSHV)-negative B-cell lymphoma with serosal spreading of the body cavity and lymphadenopathy: an autopsy case.

Kuwabara H, Nagai M, Shibanushi T, Ohmori M, Kawakami K, Asakura H.

Department of Pathology, Kagawa Medical University, Japan.

Hum Pathol 2000 Sep;31(9):1171-5 Abstract quote

CD138-positive and Kaposi's sarcoma-associated herpes virus (KSHV)-negative B cell lymphoma with serosal spreading of the body cavity and lymphadenopathy is presented.

Our lymphoma cells showed pleomorphic morphology and a clonal immunoglobulin gene rearrangement. Immunophenotypically, they lacked B- and T-cell-associated antigens but expressed strong membranous CD138 antigen along the serosa. Although our case was not conventional primary effusion lymphoma (PEL) because of the absence of KSHV and the presence of lymphadenopathy, its unique phenotype and serosal spreading were consistent with those of PEL.

Our case suggests that, irrespective of KSHV infection, some pleomorphic B cell lymphomas with membranous CD138 expression show a peculiar serosal spreading.

PROGNOSIS AND TREATMENT CHARACTERIZATION

PROGNOSTIC FACTORS

TREATMENT

Alpha interferon inhibits human herpesvirus 8 (HHV-8) reactivation in primary effusion lymphoma cells and reduces HHV-8 load in cultured peripheral blood mononuclear cells.

Monini P, Carlini F, Sturzl M, Rimessi P, Superti F, Franco M, Melucci-Vigo G, Cafaro A, Goletti D, Sgadari C, Butto' S, Leone P, Chiozzini C, Barresi C, Tinari A, Bonaccorsi A, Capobianchi MR, Giuliani M, di Carlo A, Andreoni M, Rezza G, Ensoli B.

Laboratory of Virology, Institute of Virology, University "La Sapienza"

J Virol 1999 May;73(5):4029-41 Abstract quote

Infection by human herpesvirus 8 (HHV-8) is associated with the development of Kaposi's sarcoma (KS). Since regression of KS can be achieved by treatment of the patients with alpha interferon (IFN-alpha), we analyzed the effects of IFN-alpha or anti-IFN-alpha antibodies (Ab) on HHV-8 latently infected primary effusion lymphoma-derived cell lines (BCBL-1 and BC-1) and on peripheral blood mononuclear cells (PBMC) from patients with all forms of KS and from at-risk subjects.

IFN-alpha inhibited in a dose-dependent manner the amplification of HHV-8 DNA in BCBL-1 cells induced to lytic infection with tetradecanoyl phorbol acetate (TPA). This effect was associated with the inhibition of the expression of HHV-8 nut-1 and kaposin genes that are induced early and several hours, respectively, after TPA treatment. In addition, IFN-alpha inhibited virus production and/or release from BCBL-1 cells. Inhibition of nut-1 and kaposin genes by IFN-alpha was also observed in BC-1 cells induced with n-butyrate. Conversely, the addition of anti-IFN-alpha Ab to TPA-induced BCBL-1 cells resulted in a larger number of mature enveloped particles and in a more extensive cytopathic effect due to the neutralization of the endogenous IFN produced by these cells. IFN was also produced by cultured PBMC from HHV-8-infected individuals, and this was associated with a loss of viral DNA during culture. However, the addition of anti-IFN-alpha Ab or anti-type I IFN receptor Ab promoted the maintenance of HHV-8 DNA in these cells that was associated with the detection of the latency-associated kaposin RNA. Finally, the addition of IFN-alpha reduced the HHV-8 load in PBMC.

Thus, IFN-alpha appears to have inhibitory effects on HHV-8 persistent infection of PBMC. These results suggest that, in addition to inhibiting the expression of angiogenic factors that are key to KS development, IFN-alpha may induce KS regression by reducing the HHV-8 load and/or inhibiting virus reactivation.

Anti-CD20 Monoclonal Antibody Treatment of Human Herpesvirus 8-Associated, Body Cavity-Based Lymphoma with an Unusual Phenotype in a Human Immunodeficiency Virus-Negative Patient.

Perez CL, Rudoy S.

Departamento Virologia, Instituto Nacional de Enfermedades Infecciosas-ANLIS "Dr. Carlos G. Malbran,", Buenos Aires, Argentina.

Clin Diagn Lab Immunol 2001 Sep;8(5):993-6 Abstract quote

Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma-associated herpesvirus, is a gammaherpesvirus first detected in Kaposi's sarcoma tumor cells and subsequently in primary effusion lymphoma (PEL) tumor cells and peripheral blood mononuclear cells from PEL patients. PEL has been recognized as an individual nosologic entity based on its distinctive features and consistent association with HHV-8 infection. PEL is an unusual form of body cavity-based B-cell lymphoma (BCBL). It occurs predominantly in human immunodeficiency virus (HIV)-positive patients but occasionally also in elderly HIV-negative patients.

We describe a case of PEL, with ascites, bilateral pleural effusions, and a small axillary lymphadenopathy, in a 72-year-old HIV-negative man. PCR performed on a lymph node specimen and in liquid effusion was positive for HHV-8 and negative for Epstein-Barr virus. The immunophenotype of the neoplastic cells was B CD19(+) CD20(+) CD22(+) with coexpression of CD10 and CD23 and with clonal kappa light chain rearrangement. The patient was treated with Rituximab, a chimeric (human-mouse) anti-CD20 monoclonal antibody. Thirteen months later, the patient continued in clinical remission.

This is the first report of an HHV-8-associated BCBL in an HIV-negative patient in Argentina.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Eight Edition. Mosby 1996.
Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.

Commonly Used Terms

Lymphoma

Last Updated 10/24/2002

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DISEASE ASSOCIATIONS	CHARACTERIZATION
TRANSPLANTATION
Primary effusion lymphoma after heart transplantation: a new entity associated with human herpesvirus-8. Dotti G, Fiocchi R, Motta T, Facchinetti B, Chiodini B, Borleri GM, Gavazzeni G, Barbui T, Rambaldi A. Divisione di Ematologia, Ospedali Riuniti di Bergamo, Italy.	Leukemia 1999 May;13(5):664-70 Abstract quote Deep immunosuppression and Epstein-Barr virus (EBV) infection promote the emergence of lymphoproliferative disorders in patients undergoing solid organ transplantation. In the last few years a new herpesvirus, named human herpesvirus-8 (HHV-8), has been identified in Kaposi's sarcoma and primary effusion lymphoma (PEL) developing in AIDS patients. Subsequently, the same viral DNA sequences have been identified in almost all cases of Kaposi's sarcoma emerged outside HIV infection, thus suggesting their possible pathogenetic role in this tumor. Similarly, the association between HHV-8 and PEL also emerged in cases without HIV infection, even though the total number of these patients is still limited. Here, we focus on the emergence of this unusual lymphoma in patients undergoing solid organ transplant and underline once again its association with the HHV-8. Moreover, despite the characteristic local growth of this peculiar type of lymphoma, we demonstrate at the molecular level, an early neoplastic spread to the bone marrow suggesting the need to investigate in more detail the origin of the disease, as well as the molecular mechanisms controlling its systemic dissemination.
HIV
Primary effusion lymphoma with herpesvirus 8 DNA in patients coinfected with HIV and hepatitis C virus: a report of 2 cases. Hong S, Krafft AE. Department of Pathology, College of Medicine, Howard University Hospital, Washington, DC, USA.	AIDS Read 2001 Aug;11(8):418-22 Abstract quote The primary effusion lymphoma (PEL), commonly described in patients with AIDS, is a unique subset of diffuse large cell lymphoma in which the malignant lymphocytes proliferate exclusively in serous cavities. The cytologic, immunophenotypic, and molecular features of PEL are presented from findings of 2 patients coinfected with HIV and hepatitis C virus who presented with abdominal pain. Abdominal radiography in both patients displayed marked peritoneal effusions. Cytomorphologic examination of peritoneal fluid revealed a malignant lymphoma in both. Their immunophenotypic expression was CD30 (Ki-1) and epithelial membrane antigen. Molecular analysis demonstrated human herpesvirus 8 DNA in both patients and bcl-2 oncogene rearrangement within the major breakpoint region of t(14;18) chromosome translocation in Case B only. Clinical correlation supports the current concept that PEL represents a primary HIV/AIDS-related lymphoma in effusion. Cytomorphologic examination of body cavity fluid serves as a tool for the initial diagnosis of PEL.
CASTLEMAN'S DISEASE
Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease. Ascoli V, Signoretti S, Onetti-Muda A, Pescarmona E, Della-Rocca C, Nardi F, Mastroianni CM, Gastaldi R, Pistilli A, Gaidano G, Carbone A, Lo-Coco F. Anatomia Patologica, Dipartimento di Medicina Sperimentale e Patologia, Universita La Sapienza, Roma, Italy.	J Pathol 2001 Feb;193(2):200-9 Abstract quote Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL. This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders. Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

SPECIAL STAINS/IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
SPECIAL STAINS
IMMUNOPEROXIDASE
Association of Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma with expression of the CD138/syndecan-1 antigen. Gaidano G, Gloghini A, Gattei V, Rossi MF, Cilia AM, Godeas C, Degan M, Perin T, Canzonieri V, Aldinucci D, Saglio G, Carbone A, Pinto A. Division of Internal Medicine, Department of Medical Sciences, University of Torino at Novara, Novara, Italy.	Blood 1997 Dec 15;90(12):4894-900 Abstract quote Primary effusion lymphoma (PEL) represents a novel B-cell non-Hodgkin's lymphoma (NHL) type associated with Kaposi's sarcoma-associated herpesvirus infection and typically growing as lymphomatous effusions in the body cavities. The precise B-cell subset from which PEL originates as well as the biologic mechanisms responsible for its peculiar growth pattern are unclear. In this study, we have analyzed PEL for the expression status of CD138/syndecan-1, a molecule selectively associated with late stages of B-cell differentiation and implicated in cell-to-cell and cell-to-extracellular matrix interactions. PEL patient samples (n = 7) and cell lines (n = 5) were investigated by multiple approaches, including immunocytochemistry, flow cytometry, RNA analysis, and Western blot studies. For comparison, lymphomatous effusions other than PEL (n = 13) and tissue-based NHL (n = 103) were also tested. Expression of CD138/syndecan-1 associates at high frequency with PEL (5 of 7 patient samples and 5 of 5 cell lines), whereas it is consistently absent among other lymphomatous effusions (n = 13). The CD138/syndecan-1 isoform expressed by PEL has an average molecular weight of 420 kD, which is substantially different from that of CD138/syndecan-1 molecules generally expressed by plasma cells. These data, along with previous immunophenotypic evidence, unequivocally define that PEL cells represent a preterminal stage of B-cell differentiation and may bear implications for the peculiar growth pattern of this lymphoma.
Distribution of human herpesvirus-8 latently infected cells in Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma. Dupin N, Fisher C, Kellam P, Ariad S, Tulliez M, Franck N, van Marck E, Salmon D, Gorin I, Escande JP, Weiss RA, Alitalo K, Boshoff C. Departments of Oncology and Molecular Pathology, Royal Free and University College Medical School, UCL, London, United Kingdom W1P 6BT.	Proc Natl Acad Sci U S A 1999 Apr 13;96(8):4546-51 Abstract quote Human herpesvirus 8 (HHV-8, also called KSHV) is linked to the etiopathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). The universal presence of HHV-8 in early KS has not yet been shown. We used a mAb (LN53) against latent nuclear antigen-1 (LNA-1) of HHV-8 encoded by ORF73 to study the distribution of the cell types latently infected by HHV-8 in patch, plaque, and nodular KS, MCD, and PEL. In early KS, HHV-8 is present in <10% of cells forming the walls of ectatic vessels. In nodular KS, HHV-8 is present in cells surrounding slit-like vessels and in >90% of spindle cells, but not in normal vascular endothelium. In addition, HHV-8 colocalizes with vascular endothelial growth factor receptor-3 (VEGFR-3), a marker of lymphatic and precursor endothelium. In early KS lesions, VEGFR-3 is more extensively expressed than LNA-1, indicating that HHV-8 is not inducing the proliferation of VEGFR-3-positive endothelium directly. In MCD, HHV-8 is present in mantle zone large immunoblastic B cells. No staining for LNA-1 is seen in samples from multiple myeloma, prostate cancer, and angiosarcoma, supporting the absence of any etiological link between these diseases and HHV-8.

EPIDEMIOLOGY	CHARACTERIZATION
SYNONYMS	Body cavity lymphoma AIDS associated body cavity lymphoma
INCIDENCE	Rare

LABORATORY/RADIOLOGIC/ OTHER TESTS	CHARACTERIZATION
RADIOLOGIC
LABORATORY MARKERS
PCR
Primary effusion lymphoma: cytopathologic diagnosis using in situ molecular genetic analysis for human herpesvirus 8. Wakely Jr PE Jr, Menezes G, Nuovo GJ. Department of Pathology, The Ohio State University, Columbus, Ohio.	Mod Pathol 2002 Sep;15(9):944-50 Abstract quote Primary effusion lymphoma is a form of diffuse large B-cell lymphoma with neoplastic cells largely limited to proliferation within major body cavities. Human herpes virus-8 is both integral to and required for an unequivocal diagnosis of primary effusion lymphoma. Prior methods for virus identification include DNA extraction with Southern blot analysis or in situ hybridization from paraffin-embedded samples. Our aim is to examine the utility of human herpesvirus-8 identification performed directly on smears from effusion samples by reverse transcriptase in situ polymerase chain reaction in patients with primary effusion lymphoma. Smears and cell block of body cavity fluids from five patients with effusions (three pleural, one peritoneal, and one both pleural and peritoneal) were examined microscopically by conventional Papanicolaou and Romanowsky (Diff-Quik) staining, and by reverse transcriptase in situ polymerase chain reaction for human herpesvirus-8 detection. In situ hybridization was performed also for Epstein-Barr virus (EBER-1, -2), T-cell receptor-beta, and kappa (kappa) and lambda (lambda) mRNA in all cases. Five adults ranged from 40-81 years of age. Three adults were HIV positive, one was a renal transplant recipient, and the oldest patient (Case 3) had the unusual distinction of a normal immune status. Two of three HIV-seropositive patients had concurrent Kaposi sarcoma. All samples were cytologically similar with lymphocytes having large-cell, plasmablastic, and immunoblastic morphology. Malignant cells from effusions were as follows: human herpesvirus-8 positive (all five cases), exhibited kappa monoclonal light chain (five cases), Epstein-Barr virus positive (three cases), and T-cell beta-gene receptor positive (two cases). Diffuse large B-cell lymphoma was evident in one peritoneal nodule (<10% human herpesvirus-8 positive cells in contrast to >90% positive in effusions, all kappa positive). Six other tissue specimens (lung, bone marrow, spleen, lymph node) were human herpesvirus-8 negative, and showed no evidence of lymphoma. Reverse transcriptase in situ polymerase chain reaction demonstrated near-complete restriction of human herpesvirus-8-infected malignant lymphoid cells to those in body cavities. Definitive diagnosis of primary effusion lymphoma is possible directly from cytologic smears/cell block by combining cytologic morphology with reverse transcriptase in situ polymerase chain reaction detection of human herpesvirus-8.
VIRAL LOAD
Detection rate and intratumoral virus load of human herpesvirus-8 in immunodeficiency-related B-cell lymphoid malignancies. Feuillard J, Aubin JT, Poirel L, Davi F, Kujas M, Rousselet MC, Angonin R, Raphael M, Agut H. Service d'Hematologie Biologique, Centre Hospitalier Avicenne, Bobigny, France.	J Med Virol 1997 Nov;53(3):277-81 Abstract quote Human herpesvirus-8 (HHV-8), associated with Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease, has been found in circulating B-cells and might have a causative role in B-cell malignancies associated with immunodeficiency syndromes. We determined the rate of detection and intratumoral virus load of HHV-8 by means of a semiquantitative approach in post-transplant lymphoproliferative diseases (PTLDs), AIDS-related non-Hodgkin's lymphomas (NHLs), including both Burkitt's lymphomas (BLs) and large cell lymphomas (LCLs), as well as in control groups consisting of follicular hyperplasias (FHs) and HIV-negative LCLs. HHV-8 sequences were detected at a similar rate in HIV-negative PTLDs (24%), HIV-negative LCLs (22%) and HIV-negative FHs (17%). The detection rate was significantly higher in HIV-positive BLs (73%), HIV-positive LCLs (67%), and HIV-positive FHs (65%) supporting the view of an epidemiological link between HHV-8 and HIV infections. The viral load was 10(2) genome copies per cell in the single case of primary effusion lymphoma included in the LCL group while it was 10(-3) copy per cell (median value; range: 10(-4)-10(-1)) in all the other HHV-8-positive samples. No significant difference of viral load was found according to HIV status. The virus loads of PTLDs and HIV-positive LCLs were significantly higher than those observed in HIV-positive BLs and FHs, suggesting, to some extent, that the degree of immunodeficiency may influence HHV-8 replication. However, with the exception of the single case of primary effusion lymphoma studied, the low intratumoral load of HHV-8 strongly argues against a direct causative agent of the virus in the occurrence of PTLDs and AIDS-related NHLs.

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
GENERAL
VARIANTS
SMALL BOWEL MASS
Primary Effusion Lymphoma With Subsequent Development of a Small Bowel Mass in an HIV-Seropositive Patient: A Case Report and Literature Review. Huang Q, Chang KL, Gaal K, Arber DA.	Am J Surg Pathol 2002 Oct;26(10):1363-7 Abstract quote Primary effusion lymphoma is a distinct clinicopathologic entity usually characterized by presentation as a lymphomatous body cavity effusion in the absence of a solid tumor mass or dissemination during its clinical course. This lymphoma is typically present in human immunodeficiency virus (HIV)-infected patients and frequently associated with Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV8) viral sequences. Here we report a rare case of KSHV/HHV8-associated primary effusion lymphoma with secondary involvement of the small bowel as an obstructive tumor mass in an HIV-infected man. The solid small bowel lymphoma demonstrated essentially identical morphology, immunophenotype, KSHV/HHV8 viral status, and immunoglobulin light chain rearrangements to the pleural cavity-based primary effusion lymphoma in the same patient.
SUBARACHNOID SPACE
Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma arising in the subarachnoid space. Ely SA, Powers J, Lewis D, Chang S, Rubio A, O'Leary J, Knowles DM. Department of Pathology, The Weill Medical College and Graduate School of Medical Sciences of Cornell University/New York Presbyterian Hospital, New York, USA.	Hum Pathol 1999 Aug;30(8):981-4 Abstract quote Primary effusion lymphoma (PEL) is a rare and distinctive type of B-cell non-Hodgkin's lymphoma (NHL) that occurs primarily, although not exclusively, in patients with AIDS. It usually develops as a lymphomatous effusion in the absence of a tumor mass, characteristically contains the Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8), usually also contains the Epstein-Barr virus (EBV), displays a characteristic cytomorphology bridging immunoblastic and anaplastic large cell lymphoma, often expresses an indeterminate immunophenotype, and a B-cell genotype. Thus far, PEL has been limited almost entirely to the pleural, peritoneal, and pericardial cavities. We describe a NHL occurring in a gay man with AIDS that is typical of PEL in that it arose in a body cavity or space without an associated tumor mass, displays the cytomorphology typical of PEL, is a clonal B-cell neoplasm, and contains KSHV as well as EBV. This case is singularly distinctive in that it is the first case of PEL reported to arise in the subarachnoid space. This unique case further supports the strong association between KSHV and malignant lymphoma arising in body cavities and growing as an effusion.

PROGNOSIS AND TREATMENT	CHARACTERIZATION
PROGNOSTIC FACTORS
TREATMENT
Alpha interferon inhibits human herpesvirus 8 (HHV-8) reactivation in primary effusion lymphoma cells and reduces HHV-8 load in cultured peripheral blood mononuclear cells. Monini P, Carlini F, Sturzl M, Rimessi P, Superti F, Franco M, Melucci-Vigo G, Cafaro A, Goletti D, Sgadari C, Butto' S, Leone P, Chiozzini C, Barresi C, Tinari A, Bonaccorsi A, Capobianchi MR, Giuliani M, di Carlo A, Andreoni M, Rezza G, Ensoli B. Laboratory of Virology, Institute of Virology, University "La Sapienza"	J Virol 1999 May;73(5):4029-41 Abstract quote Infection by human herpesvirus 8 (HHV-8) is associated with the development of Kaposi's sarcoma (KS). Since regression of KS can be achieved by treatment of the patients with alpha interferon (IFN-alpha), we analyzed the effects of IFN-alpha or anti-IFN-alpha antibodies (Ab) on HHV-8 latently infected primary effusion lymphoma-derived cell lines (BCBL-1 and BC-1) and on peripheral blood mononuclear cells (PBMC) from patients with all forms of KS and from at-risk subjects. IFN-alpha inhibited in a dose-dependent manner the amplification of HHV-8 DNA in BCBL-1 cells induced to lytic infection with tetradecanoyl phorbol acetate (TPA). This effect was associated with the inhibition of the expression of HHV-8 nut-1 and kaposin genes that are induced early and several hours, respectively, after TPA treatment. In addition, IFN-alpha inhibited virus production and/or release from BCBL-1 cells. Inhibition of nut-1 and kaposin genes by IFN-alpha was also observed in BC-1 cells induced with n-butyrate. Conversely, the addition of anti-IFN-alpha Ab to TPA-induced BCBL-1 cells resulted in a larger number of mature enveloped particles and in a more extensive cytopathic effect due to the neutralization of the endogenous IFN produced by these cells. IFN was also produced by cultured PBMC from HHV-8-infected individuals, and this was associated with a loss of viral DNA during culture. However, the addition of anti-IFN-alpha Ab or anti-type I IFN receptor Ab promoted the maintenance of HHV-8 DNA in these cells that was associated with the detection of the latency-associated kaposin RNA. Finally, the addition of IFN-alpha reduced the HHV-8 load in PBMC. Thus, IFN-alpha appears to have inhibitory effects on HHV-8 persistent infection of PBMC. These results suggest that, in addition to inhibiting the expression of angiogenic factors that are key to KS development, IFN-alpha may induce KS regression by reducing the HHV-8 load and/or inhibiting virus reactivation.
Anti-CD20 Monoclonal Antibody Treatment of Human Herpesvirus 8-Associated, Body Cavity-Based Lymphoma with an Unusual Phenotype in a Human Immunodeficiency Virus-Negative Patient. Perez CL, Rudoy S. Departamento Virologia, Instituto Nacional de Enfermedades Infecciosas-ANLIS "Dr. Carlos G. Malbran,", Buenos Aires, Argentina.	Clin Diagn Lab Immunol 2001 Sep;8(5):993-6 Abstract quote Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma-associated herpesvirus, is a gammaherpesvirus first detected in Kaposi's sarcoma tumor cells and subsequently in primary effusion lymphoma (PEL) tumor cells and peripheral blood mononuclear cells from PEL patients. PEL has been recognized as an individual nosologic entity based on its distinctive features and consistent association with HHV-8 infection. PEL is an unusual form of body cavity-based B-cell lymphoma (BCBL). It occurs predominantly in human immunodeficiency virus (HIV)-positive patients but occasionally also in elderly HIV-negative patients. We describe a case of PEL, with ascites, bilateral pleural effusions, and a small axillary lymphadenopathy, in a 72-year-old HIV-negative man. PCR performed on a lymph node specimen and in liquid effusion was positive for HHV-8 and negative for Epstein-Barr virus. The immunophenotype of the neoplastic cells was B CD19(+) CD20(+) CD22(+) with coexpression of CD10 and CD23 and with clonal kappa light chain rearrangement. The patient was treated with Rituximab, a chimeric (human-mouse) anti-CD20 monoclonal antibody. Thirteen months later, the patient continued in clinical remission. This is the first report of an HHV-8-associated BCBL in an HIV-negative patient in Argentina.