Kaposi's sarcoma-associated herpesvirus/human herpesvirus type 8-positive solid lymphomas: a tissue-based variant of primary effusion lymphoma

Extracavitary primary effusion lymphoma presenting as a solitary brain mass

Primary effusion lymphoma (PEL) is an uncommon B-cell lymphoma associated with human herpesvirus 8 and comprises 3-4% of all HIV-related lymphomas. It traditionally presents as a pleural, pericardial, and/or peritoneal effusion, though it can occasionally manifest as an extracavitary or solid mass in the absence of an effusion. The extracavitary or solid variant of primary effusion lymphoma has been reported in the skin, gastrointestinal tract, lung, and lymph nodes. However, very few cases have been reported in the central nervous system. We describe a case of extracavitary or solid variant of primary effusion lymphoma presenting as a brain mass in an HIV-positive man, highlighting the clinicopathologic and immunophenotypic findings of a rare entity.

Extracavitary Primary Effusion Lymphoma Affecting the Oral Cavity: A Rare Case Report

Primary effusion lymphoma (PEL) is an aggressive neoplasm often diagnosed in immunosuppressed patients demonstrating peritoneal, pleural, or pericardial effusions. This high-grade lymphoma is strongly associated with human herpesvirus 8 (HHV8) infection and most of the lesions also show the presence of Epstein-Barr virus in tumor cells, which lacks CD20 expression and reveals a plasmablastic morphology and phenotype. The extracavitary or solid variant of PEL is even rarer and usually affects the lymph nodes and is currently considered a clinical manifestation of the classic PEL. In the oral cavity, extracavitary PEL is extremely rare and only a few patients have been previously reported, with no detailed clinicopathological description. The recognition of oral extracavitary PEL is even more important given the occurrence of plasmablastic lymphoma in the oral mucosa, which shares many clinical, microscopic, and phenotypic features with PEL, therefore, demanding from pathologists the search for HHV8, especially in immunosuppressed patients, and an appropriate clinical evaluation. In this report, we aim to describe a very rare extracavitary PEL affecting the palate of a 36-year-old patient and to review the literature regarding the extracavitary presentation of this aggressive lymphoma. This report demonstrates the importance of searching for HHV8 infection in oral lymphomas with plasmablastic features.

HHV-8 associated lymphoma

PURPOSE OF REVIEW

The discovery of Kaposi sarcoma herpesvirus (KSHV) / human herpesvirus 8 (HHV-8) led to recognition of primary effusion lymphoma (PEL) as a distinct lymphoproliferative disorder. Subsequently, two other types of lymphoma have been shown to be associated with HHV-8 : HHV-8 positive diffuse large B cell lymphoma not otherwise specified and germinotropic lymphoproliferative disorder.The pathogenesis of PEL is unique as in most cases the HHV-8+ tumoral cells are coinfected with the Epstein-Barr virus (EBV), suggesting an interplay between these two herpesviruses. This article reviews advances in the field of characterization of the lymphomatous cells, pathogenesis, and targeted therapies.

RECENT FINDINGS

The gene expression profile analysis of PEL cells and the experimental coinfection of peripheral B cells with HHV-8 and EBV allow dissection of the mechanisms of lymphomagenesis and of the relative contribution of both viruses. Systemic chemotherapy regimen remains poorly effective but new therapeutic perspectives are open with the use of monoclonal antibodies, immunomodulatory drugs, and immunotherapy.

SUMMARY

HHV-8 associated lymphoma is a model for studying virus-induced lymphoproliferation and its relation with host immune response and PEL is a unique model to study the relative contribution of two herpesviruses to lymphomagenesis in coinfected cells.

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 Effusion Lymphoma: Small Bowel Recurrence After Stem Cell Transplant

Primary effusion lymphoma (PEL) is a rare AIDS-associated non-Hodgkin lymphoma, growing in the serous body cavities as a lymphomatous effusion. The endoscopic features of PEL can mimic Kaposi sarcoma (KS). We present a case where PEL presented as small intestinal masses which had a similar macroscopic appearance to KS. Endoscopic evaluation was used with biopsies which confirmed the diagnosis of PEL. PEL is a differential of gastrointestinal KS. Accurate diagnosis is crucial for prognostication in these patients. Our case emphasizes that PEL presenting as intestinal tumors can mimic KS macroscopically. Although treatment for PEL and KS includes standard chemotherapy with concurrent antiretroviral therapy, early detection of PEL can improve overall survival in these patients.

Panniculitis-Like Presentation of Extracavitary Primary Effusion Lymphoma

Primary effusion lymphoma (PEL) is defined as a HHV-8-associated large B-cell lymphoma, which favors HIV-infected young adults, typically presenting as a serous (pleural, pericardial, or peritoneal) effusion with no identifiable tumor mass. Uncommon instances of lymphoid proliferations with the same morphology, immunophenotype, and molecular features as PEL, but occurring as a solid tumor mass without serous cavities involvement, have been termed extracavitary (or solid) variant of PEL. We hereby report the exceptional case of a HIV-associated extracavitary PEL primarily localized to the skin and exhibiting a panniculitis-like presentation. Primary cutaneous presentation of extracavitary PEL is exceedingly uncommon, with only 6 cases previously described in the literature. In light of its atypical immunophenotype, the differential diagnosis in case of skin involvement by extracavitary PEL is challenging: demonstration of HHV-8 infection in neoplastic cells is of pivotal importance. Our case is further atypical in that the lymphoid proliferation underwent complete and protracted regression solely by establishment of highly active antiretroviral therapy.

Proteomic approaches to investigate gammaherpesvirus biology and associated tumorigenesis

The DNA viruses, Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), are members of the gammaherpesvirus subfamily, a group of viruses whose infection is associated with multiple malignancies, including cancer. The primary host for these viruses is humans and, like all herpesviruses, infection with these pathogens is lifelong. Due to the persistence of gammaherpesvirus infection and the potential for cancer formation in infected individuals, there is a driving need to understand not only the biology of these viruses and how they remain undetected in host cells but also the mechanism(s) by which tumorigenesis occurs. One of the methods that has provided much insight into these processes is proteomics. Proteomics is the study of all the proteins that are encoded by a genome and allows for (i) identification of existing and novel proteins derived from a given genome, (ii) interrogation of protein-protein interactions within a system, and (iii) discovery of druggable targets for the treatment of malignancies. In this chapter, we explore how proteomics has contributed to our current understanding of gammaherpesvirus biology and their oncogenic processes, as well as the clinical applications of proteomics for the detection and treatment of gammaherpesvirus-associated cancers.

Extracavitary primary effusion lymphoma recurring with syphilis in an HIV-infected patient

A 59-year-old Caucasian man infected with HIV, in remission from human herpes virus-8-positive extracavitary primary effusion lymphoma (EC-PEL), presented to a sexual health clinic with fever and rectal pain 10 weeks after a single episode of receptive anal sexual intercourse with another man. He was initially treated for a presumptive diagnosis of lymphogranuloma venereum proctitis, then for syphilis on positive serology. Rectosigmoidoscopy revealed a single ulcerated rectal mass; endoscopic biopsies confirmed the recurrence of EC-PEL. The patient received chemotherapy and went into remission. This is the first reported case of EC-PEL occurring synchronously with early syphilis, and specifically at the site of inoculation, which can be a major diagnostic challenge since both conditions may present with lymphadenopathy, mucosal involvement and constitutional symptoms. We reviewed the literature for similar cases and hypothesised that syphilis may have triggered the recurrence of this rare lymphoma.

Activity of brentuximab vedotin in AIDS-related primary effusion lymphoma

Brentuximab vedotin is active in primary effusion lymphoma, a rare CD30-positive lymphoma with an extremely poor prognosis.

High-dose Therapy and Autologous Hematopoietic Cell Transplantation as Consolidation Treatment for Primary Effusion Lymphoma

BACKGROUND

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin lymphoma. The limited disease-free survival after chemotherapy has resulted in a poor prognosis. The outcomes data for high-dose therapy followed by autologous hematopoietic cell transplantation (auto-HCT) for PEL are limited owing to the rarity of the disease.

PATIENTS AND METHODS

The present study included 9 patients with PEL from 2 major academic centers. Of these patients, 4 had received auto-HCT after high-dose therapy. Of the 9 patients, 8 (89%) had immunodeficiency (7 with human immunodeficiency virus seropositivity; 1, a solid organ transplant recipient) at the diagnosis. Human herpesvirus-8 by immunohistochemistry was positive in 8 patients. Anthracycline-based combination chemotherapy was used as first-line treatment in 7 patients; 4 underwent auto-HCT after attaining first complete remission.

RESULTS

The median follow-up of the surviving patients was 25 months (95% confidence interval [CI], 8%-29%). The 2-year progression-free and overall survival for the 8 patients who had received treatment was 58% (95% CI, 22%-95%) and 73% (95% CI, 41%-100%), respectively. The 2-year progression-free and overall survival for the patients who had received auto-HCT was 50% (95% CI, 1%-99%) and 75% (95% CI, 33%-100%), respectively. Of the 4 auto-HCT recipients, all had been in first complete remission at the time of autografting. The cumulative incidence of relapse was 50% (95% CI, 19%-100%). No deaths were attributable to auto-HCT at 2 years after autografting.

CONCLUSION

Despite the small sample size, our data have shown that consolidative auto-HCT is safe and effective and should be considered for eligible patients with PEL after demonstration of an objective response to induction chemotherapy. However, the high relapse rate remains a concern and warrants the development of new strategies to mitigate post-transplantation relapse.

Brentuximab vedotin as frontline treatment for HIV-related extracavitary primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive herpesvirus-8 (HHV-8) driven B cell non-Hodgkin's lymphoma (NHL) that is usually associated with human immunodeficiency virus (HIV) infection, and has a poor prognosis. PEL is comprised of two clinically distinct but pathologically similar variants: classic and extracavitary PEL. Based on retrospective series, treatment options include combined antiretroviral therapy (cART) in conjunction with chemotherapy regimens used in other forms of NHLs. Treatment outcomes with this approach are usually dismal and there is no standard of care. We present a case of a patient with HIV associated CD30+ extracavitary PEL unfit for multi-agent chemotherapy, who achieved a durable complete response with single agent brentuximab-vedotin and cART.

Kaposi sarcoma-associated herpesvirus/human herpesvirus 8-associated lymphoproliferative disorders

Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 is associated with multicentric Castleman disease (MCD) and primary effusion lymphoma (PEL). In MCD, infected B cells, although polyclonal, express a monotypic immunoglobulin Mλ phenotype, probably through editing toward λ light chain in mature B cells. They are considered to originate from pre-germinal center (GC) naive B cells. Both viral and human interleukin-6 contribute to the plasmacytic differentiation of these cells, and viral replication can be observed in some infected cells. PEL cells are clonal B cells considered as GC/post-GC B cells. One can also hypothesize that they originate from the same infected naive B cells and that additional factors could be responsible for their peculiar phenotype.

Kaposi's Sarcoma-Associated Herpesvirus (KSHV)-Associated Disease in the AIDS Patient: An Update

In this book chapter, we review the current knowledge of the biology and pathogenesis of Kaposi's sarcomaassociated herpesvirus (KSHV). We describe the lifecycle of KSHV, the cancers associated with this virus, as well as current treatment modalities.

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.

Primary Effusion Lymphoma without an Effusion: A Rare Case of Solid Extracavitary Variant of Primary Effusion Lymphoma in an HIV-Positive Patient

Primary effusion lymphoma (PEL) is a unique form of non-Hodgkin lymphoma, usually seen in severely immunocompromised, HIV-positive patients. PEL is related to human herpesvirus-8 (HHV-8) infection, and it usually presents as a lymphomatous body cavity effusion in the absence of a solid tumor mass. There have been very few case reports of HIV-positive patients with HHV-8-positive solid tissue lymphomas not associated with an effusion (a solid variant of PEL). In the absence of effusion, establishing an accurate diagnosis can be challenging, and a careful review of morphology, immunophenotype, and presence of HHV-8 is necessary to differentiate from other subtypes of non-Hodgkin lymphoma. Treatment involves intensive chemotherapy, and prognosis is usually poor. We present a rare case of a PEL variant in an HIV-positive patient who presented with extensive lymphadenopathy without any associated effusions.

There Are No Magic Bullets in Hematopathology: Even Immunostains for CD20 and CD3 Can Get You Into Trouble

Immunohistochemistry is a powerful tool for the diagnosis and subclassification of hematolymphoid neoplasms. However, the expression of certain markers is not always as expected, and unusual patterns of staining can lead to misdiagnosis. CD20 and CD3 are our most commonly used markers for identification of B cells and T cells, respectively, and they almost always yield reliable, specific staining. This discussion focuses on diagnostic pitfalls related to the use of immunohistochemistry for CD20 and CD3 in hematopathology, and specifically on diagnostic challenges that arise when (1) CD20 is not expressed in B-cell lymphomas, when (2) CD20 is expressed in plasma cell neoplasms and T-cell lymphomas, and when (3) CD3 is expressed in B-cell lymphomas and Hodgkin lymphoma.

A KSHV microRNA enhances viral latency and induces angiogenesis by targeting GRK2 to activate the CXCR2/AKT pathway

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). Most tumor cells in these malignancies are latently infected by KSHV. Thus, viral latency is critical for the development of tumor and induction of tumor-associated angiogenesis. KSHV encodes more than two dozens of miRNAs but their roles in KSHV-induced angiogenesis remains unknown. We have recently shown that miR-K12-3 (miR-K3) promoted cell migration and invasion by targeting GRK2/CXCR2/AKT signaling (PLoS Pathog, 2015;11(9):e1005171). Here, we further demonstrated a role of miR-K3 and its induced signal pathway in KSHV latency and KSHV-induced angiogenesis. We found that overexpression of miR-K3 not only promoted viral latency by inhibiting viral lytic replication, but also induced angiogenesis. Further, knockdown of GRK2 inhibited KSHV replication and enhanced KSHV-induced angiogenesis by enhancing the CXCR2/AKT signals. As a result, blockage of CXCR2 or AKT increased KSHV replication and decreased angiogenesis induced by PEL cells in vivo. Finally, deletion of miR-K3 from viral genome reduced KSHV-induced angiogenesis and increased KSHV replication. These findings indicate that the miR-K3/GRK2/CXCR2/AKT axis plays an essential role in KSHV-induced angiogenesis and promotes KSHV latency, and thus may be a potential therapeutic target of KSHV-associated malignancies.

Epstein-Barr virus associated lymphomas in people with HIV

PURPOSE OF REVIEW

The present review summarizes the association of the different histotypes of Epstein-Barr virus (EBV)-associated lymphomas with known genetic lesions and/or oncogenic viruses. A more comprehensive understanding of the complex interplay existing between genetic abnormalities of tumor cells and the viral contribution to the development of EBV-associated lymphomas is pivotal for the development of more effective treatments.

RECENT FINDINGS

Recent evidence indicates that HIV may contribute to lymphomagenesis by acting directly on B lymphocytes as a critical microenvironmental factor. The pathogenesis of EBV-associated lymphomas in patients with HIV infection is considered the result of the concerted action of different factors, mainly including impaired immune surveillance, genetic alterations, and concomitant viral infection (EBV and HIV).

SUMMARY

Immunodeficiency states usually increase susceptibility to cancer as a result of reduced immune surveillance and enhanced chances for virus-driven oncogenesis. Lymphoma remains the most frequent neoplastic cause of death among patients infected with HIV. Several of the HIV-associated lymphomas are related to EBV infection. EBV-associated lymphomas in patients infected with HIV are heterogeneous, not only pathologically but also in terms of pathogenetic pathways and cellular derivation.

KSHV-associated extracavitary primary effusion lymphoma in an HIV seronegative patient: a case report and review of the literature

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin's lymphoma presenting as a lymphomatous effusion and absence of a solid tumor mass. Extracavitary PEL (EC-PEL) is a subtype of PEL with the absence of an effusion but presence of solid tumor. PEL and EC-PEL share the same histopathologic and immunophenotypic features. Kaposi sarcoma-associated herpesvirus (KSHV) positivity is seen universally in these malignancies and is a requisite for diagnosis. Most cases are seen to occur in HIV positive individuals. We present a unique case of a 21-year-old male who presented with ongoing chest pain and right hip pain found to have an extensive lytic lesion of the right iliac bone, a paratracheal mass and a large pelvic mass. All the involved sites were FDG (F-18 fluorodeoxyglucose)-avid on PET-CT scan. The patient was seronegative for HIV with no risk factors for immunosuppression. A biopsy of the pelvic mass and bone marrow showed large atypical cells with irregular multi-lobulated nuclei, prominent nucleoli, and abundant amphophilic cytoplasm. The cells were positive for MUM1, in situ hybridization for EBV-encoded RNA (EBER), and KSHV, while negative for B-cell and T-cell markers. The patient was treated with six cycles of DA-EPOCH with a follow up PET scan showing a decrease in size of the masses and bone lesion and conversion to non-FDG-avid status. To the best of our knowledge, our case is the first in published English literature with bone involvement with EC-PEL regardless of HIV status. We review the reported cases of EC-PEL including their presentation, diagnostic features, treatment and outcomes.

B-cell Lymphoproliferative Disorders Associated with Primary and Acquired Immunodeficiency

The diagnosis of lymphoproliferative disorders associated with immunodeficiency can be challenging because many of these conditions have overlapping clinical and pathologic features and share similarities with their counterparts in the immunocompetent setting. There are subtle but important differences between these conditions that are important to recognize for prognostic and therapeutic purposes. This article provides a clinicopathologic update on how understanding of these B-cell lymphoproliferations in immunodeficiency has evolved over the past decade.

Primary effusion lymphoma involving cerebrospinal fluid, deep cervical lymph nodes and adenoids. Report of a case supporting the lymphatic connection between brain and lymph nodes

We describe an unusual presentation of primary effusion lymphoma in CSF of a 45-year-old HIV-positive man, with no evidence of involvement of pleural, peritoneal or pericardial cavities. Cytologic examination and flow cytometric analysis suggested the diagnosis, eventually made in an excised deep cervical lymph node, in which the neoplastic cells involved selectively the sinuses. This case represents the fifth reported example of CSF involvement by this type of lymphoma, and supports the alleged connection between CSF and cervical lymph nodes via lymphatic vessels. Interestingly, review of an adenoidectomy specimen obtained 9 months before presentation for nonspecific complaints showed rare clusters of neoplastic cells involving surface epithelium and chorium, a finding that might represent a homing mechanism and implies an asymptomatic, occult phase of lymphoma development.

Human Herpesvirus Type 8-associated Large B-cell Lymphoma: A Nonserous Extracavitary Variant of Primary Effusion Lymphoma in an HIV-infected Man: A Case Report and Review of the Literature

BACKGROUND

Primary effusion lymphoma (PEL) is a rare non-Hodgkin lymphoma subtype primarily seen in human immunodeficiency virus (HIV)-infected individuals with low CD4(+) cell counts and elevated HIV viral loads. It has always been associated with human herpesvirus type 8 (HHV-8) and in 80% of cases has also been associated with Epstein-Barr virus (EBV). Less commonly, PEL has presented in patients with advanced age and other conditions associated with an altered immunity, including malignancy, liver cirrhosis, and immunosuppressive medications. It is a tumor of B-cell lineage; however, it shows a "null" phenotype, rarely expressing pan-B cell surface antigens. It will usually express CD45, CD30, CD38, CD138, and MUM1 and is characterized by lymphomatous effusions in body cavities but not lymphadenopathy. It is an aggressive lymphoma, with an average median survival of < 1 year. HHV-8-associated large B-cell lymphoma (HHV-8-LBL) is a second variant of PEL that is both solid and extracavitary. It has immunoblastic and/or anaplastic morphologic features and a distinct immunohistochemical staining pattern. It could also have a different clinical presentation than that of classic PEL.

MATERIALS AND METHODS

We describe the case of a 57-year-old HIV-infected man who presented with a slow-growing and asymptomatic abdominal mass. Examination of an excisional biopsy specimen showed malignant large cells with prominent cytoplasm that were positive for pan-B cell antigen CD20, HHV-8, and EBV and negative for CD138, CD10, BCL-6, CD3, and CD30. The Ki-67 labeling index was 90%. The diagnosis was stage IIIA HHV-8-LBL, and he was treated with 6 cycles of R-EPOCH (rituximab, etoposide, vincristine, doxorubicin, cyclophosphamide, and prednisone) infusion chemotherapy. At 12 months after treatment, he was in complete remission. We also performed a Medline and Embase search to better understand the clinical findings of our patient and the unique attributes of HHV-8-LBL. Focusing our search on English language studies, we identified 83 cases of HHV-8-LBL without an effusion component. We compared these 83 cases with 118 reported cases of classic PEL.

RESULTS

The median age of the patients with HHV-8-LBL was 41 years (range, 24-77), and 96% of the cases were associated with HIV. The median age of the patients with classic PEL was 41 years (range, 26-86), and 96% of the cases were associated with HIV. Of those with HHV-8-LBL, 31 of 61 (51%) had a pre-existing diagnosis of acquired immunodeficiency syndrome (AIDS) and 47 of 63 (75%) were coinfected with EBV. In contrast, 69 of 96 patients (72%) with classic PEL had a pre-existing AIDS diagnosis and 40 of 49 (82%) were coinfected with EBV. The mean CD4(+) count of the HHV-8-LBL patients was 256 cells/μL (range, 18-1126 cells/μL) compared with 139 cells/μL (range, 2-557 cells/μL) in the classic PEL patients. The median survival time for both groups was similar at 5.5 months (range, 25 days to ≥ 25 months) for patients with HHV-8-LBL and 4 months (range, 2 days to ≥ 113 months) for those with classic PEL. More patients with HHV-8-LBL were alive at the last follow-up point (59% vs. 18%). The percentage of patients achieving complete remission was 54% (30 of 56) and 36% (32 of 89) for HHV-8-LBL and classic PEL, respectively.

CONCLUSION

Our patient's high CD4(+) cell count, the lack of a pre-existing AIDS diagnosis, and the excellent response to chemotherapy highlights that HHV-8-LBL might have distinct clinical features and possibly a better response to chemotherapy than classic PEL. HHV-8-LBL should be included in the differential diagnosis of HIV patients with solid lesions. It is essential that patients' Centers for Disease Control and Prevention HIV clinical status and HIV viral load at the diagnosis of PEL and HHV-8-LBL be reported and that the reported clinical results include longer term follow-up data. Only then will a more complete clinical picture of this little-appreciated and little-understood PEL variant be defined.

Classic and extracavitary primary effusion lymphoma in 51 HIV-infected patients from a single institution

Human immunodeficiency virus (HIV)-associated primary effusion lymphoma (PEL) is a rare B-cell non-Hodgkin lymphoma with poor prognosis. Lymphoma cells are always infected with human herpesvirus-8 (HHV-8) and in most cases coinfected with Epstein-Barr virus. In classic presentation, PEL is characterized by body cavity effusions with or without mass lesions. A variant with only extracavitary localization has also been described. We report on a large single-center series of patients with PEL in the era of combined antiretroviral therapy (cART). The main objective was to compare the characteristics and the outcome of patients with classic (n = 34) and extracavitary (n = 17) variant PEL. At PEL diagnosis, no major difference was observed between the two groups in terms of demographic and HIV characteristics. Extracavitary localizations were exclusively nodal in six patients and involved various organs in 11 patients. Another HHV-8-associated disease was observed in 31 patients, Kaposi sarcoma in 25, and multicentric Castleman disease in 18 patients, without difference between the two groups. Thirty-two patients were treated with CHOP associated with high-dose methotrexate, 13 were treated with CHOP-derived regimen alone, and six patients received low-dose/no chemotherapy. Complete remission was achieved in 21 (62%) and seven (41%) patients of the classic and extracavitary groups, respectively. The median overall survival (OS) was 10.2 months. Despite a higher disease-free survival in the extracavitary group, there was no difference in OS between the two variants. Based on this series, characteristics of classic and extracavitary variants were very close. Although prognosis of PEL remains very severe in cART era, the median survival compares favorably with earlier series.

Targeting HGF/c-MET induces cell cycle arrest, DNA damage, and apoptosis for primary effusion lymphoma

Kaposi sarcoma-associated herpesvirus (KSHV) is a principal causative agent of primary effusion lymphoma (PEL) with a poor prognosis in immunocompromised patients. However, it still lacks effective treatment which urgently requires the identification of novel therapeutic targets for PEL. Here, we report that the hepatocyte growth factor (HGF)/c-MET pathway is highly activated by KSHV in vitro and in vivo. The selective c-MET inhibitor, PF-2341066, can induce PEL apoptosis through cell cycle arrest and DNA damage, and suppress tumor progression in a xenograft murine model. By using microarray analysis, we identify many novel genes that are potentially controlled by HGF/c-MET within PEL cells. One of the downstream candidates, ribonucleoside-diphosphate reductase subunit M2 (RRM2), also displays the promising therapeutic value for PEL treatment. Our findings provide the framework for development of HGF/c-MET-focused therapy and implementation of clinical trials for PEL patients.

Bub1 in Complex with LANA Recruits PCNA To Regulate Kaposi's Sarcoma-Associated Herpesvirus Latent Replication and DNA Translesion Synthesis

Latent DNA replication of Kaposi's sarcoma-associated herpesvirus (KSHV) initiates at the terminal repeat (TR) element and requires trans-acting elements, both viral and cellular, such as ORCs, MCMs, and latency-associated nuclear antigen (LANA). However, how cellular proteins are recruited to the viral genome is not very clear. Here, we demonstrated that the host cellular protein, Bub1, is involved in KSHV latent DNA replication. We show that Bub1 constitutively interacts with proliferating cell nuclear antigen (PCNA) via a highly conserved PIP box motif within the kinase domain. Furthermore, we demonstrated that Bub1 can form a complex with LANA and PCNA in KSHV-positive cells. This strongly indicated that Bub1 serves as a scaffold or molecular bridge between LANA and PCNA. LANA recruited PCNA to the KSHV genome via Bub1 to initiate viral replication in S phase and interacted with PCNA to promote its monoubiquitination in response to UV-induced damage for translesion DNA synthesis. This resulted in increased survival of KSHV-infected cells.

IMPORTANCE

During latency in KSHV-infected cells, the viral episomal DNA replicates once each cell cycle. KSHV does not express DNA replication proteins during latency. Instead, KSHV LANA recruits the host cell DNA replication machinery to the replication origin. However, the mechanism by which LANA mediates replication is uncertain. Here, we show that LANA is able to form a complex with PCNA, a critical protein for viral DNA replication. Furthermore, our findings suggest that Bub1, a spindle checkpoint protein, serves as a scaffold or molecular bridge between LANA and PCNA. Our data further support a role for Bub1 and LANA in PCNA-mediated cellular DNA replication processes as well as monoubiquitination of PCNA in response to UV damage. These data reveal a therapeutic target for inhibition of KSHV persistence in malignant cells.

Chromatinization of the KSHV Genome During the KSHV Life Cycle

Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma herpesvirus family and is the causative agent of various lymphoproliferative diseases in humans. KSHV, like other herpesviruses, establishes life-long latent infection with the expression of a limited number of viral genes. Expression of these genes is tightly regulated by both the viral and cellular factors. Recent advancements in identifying the expression profiles of viral transcripts, using tilling arrays and next generation sequencing have identified additional coding and non-coding transcripts in the KSHV genome. Determining the functions of these transcripts will provide a better understanding of the mechanisms utilized by KSHV in altering cellular pathways involved in promoting cell growth and tumorigenesis. Replication of the viral genome is critical in maintaining the existing copies of the viral episomes during both latent and lytic phases of the viral life cycle. The replication of the viral episome is facilitated by viral components responsible for recruiting chromatin modifying enzymes and replication factors for altering the chromatin complexity and replication initiation functions, respectively. Importantly, chromatin modification of the viral genome plays a crucial role in determining whether the viral genome will persist as latent episome or undergo lytic reactivation. Additionally, chromatinization of the incoming virion DNA, which lacks chromatin structure, in the target cells during primary infection, helps in establishing latent infection. Here, we discuss the recent advancements on our understating of KSHV genome chromatinization and the consequences of chromatin modifications on viral life cycle.

Primary effusion lymphoma presenting as a cutaneous intravascular lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive lymphoma that arises in the context of immunosuppression and is characterized by co-infection with Epstein-Barr virus (EBV) and human herpesvirus-8/Kaposi sarcoma-associated herpesvirus (HHV-8/KSHV). It was originally described as arising in body cavity effusions, but presentation as a mass lesion (extracavitary PEL) is now recognized. Here, we describe a case of PEL with an initial presentation as an intravascular lymphoma with associated skin lesions. The patient was a 53-year-old man with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) who presented with fevers, weight loss and skin lesions concerning for Kaposi sarcoma (KS). A skin biopsy revealed no evidence of KS; however, dermal vessels contained large atypical cells that expressed CD31 and plasma cell markers but lacked most B- and T-cell antigens. The atypical cells expressed EBV and HHV-8. The patient subsequently developed a malignant pleural effusion containing the same neoplastic cell population. The findings in this case highlight the potential for unusual intravascular presentations of PEL in the skin as well as the importance of pursuing microscopic diagnosis of skin lesions in immunosuppressed patients.

KSHV: pathways to tumorigenesis and persistent infection

Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These cancers often occur in the context of immunosuppression, which has made KSHV-associated malignancies an increasing global health concern with the persistence of the AIDS epidemic. KSHV has also been linked to several acute inflammatory diseases. KSHV exists between a lytic and latent lifecycle, which allows the virus to transition between active replication and quiescent infection. KSHV encodes a number of proteins and small RNAs that are thought to inadvertently transform host cells while performing their functions of helping the virus persist in the infected host. KSHV also has an arsenal of components that aid the virus in evading the host immune response, which help the virus establish a successful lifelong infection. In this comprehensive chapter, we will discuss the diseases associated with KSHV infection, the biology of latent and lytic infection, and individual proteins and microRNAs that are known to contribute to host cell transformation and immune evasion.

Extracavitary primary effusion lymphoma presenting as a cutaneous tumor: a case report and literature review

Primary effusion lymphoma is an unusual form of aggressive B-cell lymphoma universally associated with human herpesvirus 8 (HHV8) that involves mostly human immunodeficiency virus (HIV)-infected patients. Characteristically, it presents as a malignant serous effusion involving body cavities, but without associated tumor mass. Exceptionally, HHV8-positive lymphomas with features identical to primary effusion lymphoma may present as mass lesions in the absence of cavity effusions along the course of the disease, and are regarded as extracavitary or solid variants of the disorder. These rare forms are extremely rare in the skin. We report a case of extracavitary primary effusion lymphoma arising in a HIV-infected male, who presented with two subcutaneous masses involving the skin of the abdominal and inguinal regions as the first manifestation of the process. Kaposi sarcoma was not present in the skin surface or mucous membranes. Extensive studies failed to demonstrate involvement of other organs and the case was considered as an example of extracavitary primary effusion lymphoma originating primarily in the skin. Herein, we review the few reported cases of solid primary effusion lymphoma involving the skin in order to delineate the clinicopathologic, immunohistochemical and molecular characteristics of this rare lymphoma in the skin.

Diagnosis and management of lymphomas and other cancers in HIV-infected patients

Despite the introduction of highly active antiretroviral therapy or combination antiretroviral therapy (HAART and cART, respectively) patients infected with HIV might develop certain types of cancer more frequently than uninfected people. Lymphomas represent the most frequent malignancy among patients with HIV. Other cancer types that have increased in these patients include Kaposi sarcoma, cancer of the cervix, anus, lung and liver. In the post-HAART era, however, patients with HIV have experienced a significant improvement in their morbidity, mortality and life expectancy. This Review focuses on the different types of lymphomas that generally occur in patients with HIV. The combination of cART and antineoplastic treatment has resulted in remarkable prolongation of disease-free survival and overall survival among patients with HIV who develop lymphoma. However, the survival in these patients still lags behind that of patients with lymphoma who are not infected with HIV. We also provide an update of epidemiological data, diagnostic issues, and strategies regarding the most-appropriate management of patients with both HIV and lymphomas.

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.

HHV-8-positive and EBV-positive intravascular lymphoma: an unusual presentation of extracavitary primary effusion lymphoma

Intravascular lymphomas are rare and aggressive hematolymphoid tumors. Here, we describe a human herpesvirus type-8 (HHV-8)/Kaposi sarcoma-associated herpesvirus-positive and Epstein-Barr virus (EBV)-positive intravascular lymphoma. The patient was a 59-year-old human immunodeficiency virus-positive man who presented with diarrhea, abdominal pain, fevers, night sweats, and weight loss. Radiographic studies of the abdomen and pelvis revealed numerous subcentimeter nodules within the subcutaneous fat that lacked connection to the skin. An excisional biopsy demonstrated large atypical cells within vessels in the deep subcutaneous fat, and many of the vessels contained extensive organizing thrombi. The atypical cells lacked strong expression of most B-cell markers but were positive for MUM-1 and showed partial expression of several T-cell markers. An immunohistochemical stain for HHV-8 and an in situ hybridization for EBV were both positive in the neoplastic cells. The disease had a rapidly progressive and fatal course. This lymphoma appears to represent an entirely intravascular form of primary effusion lymphoma and highlights the propensity for HHV-8 and EBV-positive lymphoid neoplasms to show aberrant expression of T-cell markers, illustrates the utility of skin biopsies for the diagnosis of intravascular lymphoma, and suggests that biopsies to evaluate for intravascular lymphoma should be relatively deep and include subcutaneous fat.

Systematic analysis of a xenograft mice model for KSHV+ primary effusion lymphoma (PEL)

Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL), which arises preferentially in the setting of infection with human immunodeficiency virus (HIV). Even with standard cytotoxic chemotherapy, PEL continues to cause high mortality rates, requiring the development of novel therapeutic strategies. PEL xenograft models employing immunodeficient mice have been used to study the in vivo effects of a variety of therapeutic approaches. However, it remains unclear whether these xenograft models entirely reflect clinical presentations of KSHV(+) PEL, especially given the recent description of extracavitary solid tumor variants arising in patients. In addition, effusion and solid tumor cells propagated in vivo exhibit unique biology, differing from one another or from their parental cell lines propagated through in vitro culture. Therefore, we used a KSHV(+) PEL/BCBL-1 xenograft model involving non-obese diabetic/severe-combined immunodeficient (NOD/SCID) mice, and compared characteristics of effusion and solid tumors with their parent cell culture-derived counterparts. Our results indicate that although this xenograft model can be used for study of effusion and solid lymphoma observed in patients, tumor cells in vivo display unique features to those passed in vitro, including viral lytic gene expression profile, rate of solid tumor development, the host proteins and the complex of tumor microenvironment. These items should be carefully considered when the xenograft model is used for testing novel therapeutic strategies against KSHV-related lymphoma.

Combination of arsenic and interferon-α inhibits expression of KSHV latent transcripts and synergistically improves survival of mice with primary effusion lymphomas

Background

Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphomas (PEL). PEL cell lines infected with KSHV, but negative for Epstein-Barr virus have a tumorigenic potential in non-obese diabetic/severe combined immunodeficient mice and result in efficient engraftment and formation of malignant ascites with notable abdominal distension, consistent with the clinical manifestations of PEL in humans.

Methodology/Principal Findings

Using this preclinical mouse model, we demonstrate that the combination of arsenic trioxide and interferon-alpha (IFN) inhibits proliferation, induces apoptosis and downregulates the latent viral transcripts LANA-1, v-FLIP and v-Cyc in PEL cells derived from malignant ascites. Furthermore, this combination decreases the peritoneal volume and synergistically increases survival of PEL mice.

Conclusion/Significance

These results provide a promising rationale for the therapeutic use of arsenic/IFN in PEL patients.

Lymphomas occurring specifically in HIV-infected patients: from pathogenesis to pathology

Lymphomas that develop in HIV positive patients are predominantly aggressive B-cell malignancies. The most common HIV-associated lymphomas are Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). Lymphomas that occur specifically in HIV positive patients include primary effusion lymphoma (PEL) and its solid variants, plasmablastic lymphoma of the oral cavity type and lymphoma associated with Kaposi sarcoma herpesvirus (KSHV)-related multicentric Castleman disease. These lymphomas, together with BL and immunoblastic lymphoma subtypes with plasmacytoid differentiation, carry Epstein-Barr virus (EBV) infection and display a phenotype related to plasma cells. Globally, EBV is identified in the neoplastic cells of approximately 40% of HIV-associated lymphomas, but the detection of EBV varies considerably with the site of presentation and the histological subtype. EBV infection occurs in 80-100% of primary central nervous system lymphomas and PELs, 80% of DLBCLs with immunoblastic-plasmacytoid features, and 30-50% of BL-plasmacytoid. KSHV is specifically associated with PEL, which usually occurs in a setting of profound immunosuppression. Current knowledge about HIV-associated lymphomas can be summarized as follows: (1) lymphomas specifically occurring in patients with HIV infection are closely linked to other viral diseases; (2) most of these lymphomas exhibit plasmablastic differentiation.

Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma tumor formation in NOD/SCID mice is inhibited by neomycin and neamine blocking angiogenin's nuclear translocation

Angiogenin (ANG) is a 14-kDa multifunctional proangiogenic secreted protein whose expression level correlates with the aggressiveness of several tumors. We observed increased ANG expression and secretion in endothelial cells during de novo infection with Kaposi's sarcoma-associated herpesvirus (KSHV), in cells expressing only latency-associated nuclear antigen 1 (LANA-1) protein, and in KSHV latently infected primary effusion lymphoma (PEL) BCBL-1 and BC-3 cells. Inhibition of phospholipase Cγ (PLCγ) mediated ANG's nuclear translocation by neomycin, an aminoglycoside antibiotic (not G418-neomicin), resulted in reduced KSHV latent gene expression, increased lytic gene expression, and increased cell death of KSHV(+) PEL and endothelial cells. ANG detection in significant levels in KS and PEL lesions highlights its importance in KSHV pathogenesis. To assess the in vivo antitumor activity of neomycin and neamine (a nontoxic derivative of neomycin), BCBL-1 cells were injected intraperitoneally into NOD/SCID mice. We observed significant extended survival of mice treated with neomycin or neamine. Markers of lymphoma establishment, such as increases in animal body weight, spleen size, tumor cell spleen infiltration, and ascites volume, were observed in nontreated animals and were significantly diminished by neomycin or neamine treatments. A significant decrease in LANA-1 expression, an increase in lytic gene expression, and an increase in cleaved caspase-3 were also observed in neomycin- or neamine-treated animal ascitic cells. These studies demonstrated that ANG played an essential role in KSHV latency maintenance and BCBL-1 cell survival in vivo, and targeting ANG function by neomycin/neamine to induce the apoptosis of cells latently infected with KSHV is an attractive therapeutic strategy against KSHV-associated malignancies.

Primary Effusion Lymphoma

Primary effusion lymphoma is a large cell non-Hodgkin lymphoma localized predominantly in body cavities and occasionally in extracavitary regions. It presents with characteristic lymphomatous effusions in the absence of solid tumor masses, and pleural, peritoneal, and pericardial spaces are most often involved. It is typically associated with human herpesvirus 8 infection in immunocompromised individuals, in the setting of human immunodeficiency virus infection, organ transplantation, or in rare cases advanced age. Histologically, primary effusion lymphoma is characterized by atypical lymphoid cells of B-cell lineage with large nuclei and prominent nucleoli. Demonstration of human herpesvirus 8 latent antigens is required for diagnosis, and treatment modalities are limited at this time. In this review, we aim to summarize clinicopathologic features of this rare and unique entity.

Simultaneous presentation of Kaposi sarcoma and HHV8-associated large B-cell lymphoma in the same lymph node: A rare diagnosis in an HIV-negative patient

PATIENT

Female, 18 FINAL DIAGNOSIS: Simultanous presentation of Kaposi Sarcoma and Lymphoma Symptoms: -

MEDICATION

- Clinical Procedure: - Specialty: Oncology.

OBJECTIVE

Rare disease.

BACKGROUND

KSHV/HHV-8 is associated with Kaposi's sarcoma (KS) as well as with a few categories of lymphoproliferative diseases, mostly occurring in patients with HIV infection/AIDS. Although the association between lymphomas and Kaposi's sarcoma has been described, the simultaneous presence of the 2 entities within the same organ is rare and mainly associated with HIV/ AIDS.

CASE REPORT

We report a case of simultaneous occurrence of Kaposi's sarcoma and large B-cell lymphoma in the same lymph node in a 18-year-old African woman who was HIV-negative. We found concurrent infection with Kaposi's sarcoma herpes virus (KSHV) and Epstein-Barr virus (EBV), confirmed by PCR amplification of DNA obtained from distinct tumor areas selected in the paraffin block.

CONCLUSIONS

The possibility of occurrence of 2 lesions with distinct features in the same organ may be unexpected for pathologists performing fine-needle aspiration cytology (FNAC) evaluation but must be considered, even in HIV-negative individuals, despite its rare occurrence, as was demonstrated by this case.

Establishment of a CD4-positive cell line from an AIDS-related primary effusion lymphoma

Primary effusion lymphoma (PEL) presents as a serous lymphomatous effusion without tumor masses exclusively in body cavities and mainly occurs in human immunodeficiency virus-1 (HIV-1)-infected patients. We established a new PEL cell line, designated GTO, from the pericardial effusion of a 39-year-old Japanese patient with acquired immunodeficiency syndrome-related PEL. This cell line was infected with human herpesvirus-8, but not with Epstein-Barr virus. Southern blot hybridization demonstrated that GTO cells display monoclonal rearrangement of the IgH gene, suggesting clonal B cell proliferation. GTO cells weakly express or lack T cell-associated markers (CD3, CD5, CD8), the majority of B cell-associated markers (CD19, CD20, CD21, CD79a), the α chains of β 2 integrins (CD11a, CD11b, CD11c), HLA-DR, CD30, and surface immunoglobulin (sIgM, sIgG sIgκ, sIgλ), TCR (α/β, γδ), but express CD45, and post-germinal center B cell/plasma cell-associated antigens (CD38, CD138). They also express a high level of cell-surface CD4 and can be infected by HIV-1. Immunodeficient mice intraperitoneally xenografted with GTO cells developed ascites containing lymphoma cells. The establishment of GTO and a GTO xenograft mouse model may help to provide insights toward a better understanding of the pathogenesis of PEL and the relationship between HIV-1 and HHV-8.

Lymphoid Proliferations Associated With Human Immunodeficiency Virus Infection

Context.—Individuals who are immune deficient are at an increased risk for developing lymphoproliferative lesions and lymphomas. Human immunodeficiency virus (HIV) infection is 1 of 4 clinical settings associated with immunodeficiency recognized by the World Health Organization (WHO) in which there is an increased incidence of lymphoma and other lymphoproliferative disorders.

Objectives.—To describe the major categories of benign lymphoid proliferations, including progressive HIV-related lymphadenopathy, benign lymphoepithelial cystic lesions, and multicentric Castleman disease, as well as the different types of HIV-related lymphomas as defined by the WHO. The characteristic morphologic, immunophenotypic, and genetic features of the different entities will be discussed in addition to some of the pathogenetic mechanisms.

Data Sources.—The WHO classification of tumors of hematopoietic and lymphoid tissues (2001 and 2008), published literature from PubMed (National Library of Medicine), published textbooks, and primary material from the authors' current and previous institutions.

Conclusions.—HIV infection represents one of the clinical settings recognized by the WHO in which immunodeficiency-related lymphoproliferative disorders may arise. Although most lymphomas that arise in patients with HIV infection are diffuse, aggressive B-cell lesions, other lesions, which are “benign” lymphoid proliferations, may also be associated with significant clinical consequences. These lymphoproliferations, like many other immunodeficiency-associated lymphoproliferative disorders, are often difficult to classify. Studies of HIV-associated lymphoid proliferations will continue to increase our understanding of both the immune system and lymphomagenesis.

Extracavitary manifestation of primary effusion lymphoma as a right atrial mass

Primary effusion lymphoma (PEL) is a subset of large B cell lymphomas and has been mostly associated with human immunodeficiency virus infection. Rare cases have been reported in organ transplant recipients and chronic hepatitis C patients. It typically presents as an effusion in the pleural and pericardial spaces but rarely disseminates. However, involvement of the gastrointestinal tract, lymph nodes and bone marrow has been reported. Diagnosis is based on characteristic clinical, histopathological and immunohistochemical features. We present a case with a right atrial mass which tested positive for human herpes virus 8 (HHV-8), CD20, CD30 and lambda light chains and negative for CD138, kappa light chain, PAX5, Epstein-Barr virus, latent membrane protein 1, CD2, CD3, CD8 and CD56. Bilateral pleural effusions and pericardial effusions were noted which tested positive for HHV-8, CD30 and CD45. The patient responded well to the R-EPOCH regimen with complete resolution of the effusions and a significant decrease in the size of the right atrial mass. This case report illustrates the atypical manifestation of PEL as a right atrial mass.