High incidence of Kaposi sarcoma-associated herpesvirus infection in HIV-related solid immunoblastic/plasmablastic diffuse large B-cell lymphoma

Simian homologues of human herpesviruses and implications for novel viral introduction to free-living mountain gorillas

The endangered mountain gorilla (Gorilla beringei beringei) in Rwanda, Uganda, and the Democratic Republic of Congo is frequently in contact with humans through tourism, research activities, and illegal entry of people into protected gorilla habitat. Herpesviruses, which are ubiquitous in primates, have the potential to be shared in any setting where humans and gorillas share habitat. Based on serological findings and clinical observations of orofacial ulcerated lesions resembling herpetic lesions, an alpha-herpesvirus resembling human herpes simplex virus type 1 (HSV-1) has long been suspected to be present in human-habituated mountain gorillas in the wild. While the etiology of orofacial lesions in the wild has not been confirmed, HSV-1 has been suspected in captively-housed mountain gorillas and confirmed in a co-housed confiscated Grauer's gorilla (Gorilla beringei graueri). To better characterize herpesviruses infecting mountain gorillas and to determine the presence/absence of HSV-1 in the free-living population, we conducted a population-wide survey to test for the presence of orally shed herpesviruses. DNA was extracted from discarded chewed plants collected from 294 individuals from 26 groups, and samples were screened by polymerase chain reaction using pan-herpesvirus and HSV-1-specific assays. We found no evidence that human herpesviruses had infected free-ranging mountain gorillas. However, we found gorilla-specific homologs to human herpesviruses, including cytomegaloviruses (GbbCMV-1 and 2), a lymphocryptovirus (GbbLCV-1), and a new rhadinovirus (GbbRHV-1) with similar characteristics (i.e., timing of primary infection, shedding in multiple age groups, and potential modes of transmission) to their human counterparts, human cytomegalovirus, Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, respectively.

Rare EBV-associated B cell neoplasms of the gastrointestinal tract

EBV-driven B cell neoplasms can rarely present as an extranodal mass in the gastrointestinal tract and can be missed, even by experienced pathologists, because of this uncommon presentation. A selection of these neoplasms, namely EBV-positive diffuse large B cell lymphoma, not otherwise specified (DLBCL NOS), EBV-positive mucocutaneous ulcer (EBV MCU), extracavitary primary effusion lymphoma (EPEL), and EBV-positive Burkitt lymphoma, will be discussed in the present review. Besides the common thread of EBV positivity, these lymphoproliferative disorders arise in unique clinical settings that are often associated with immunodeficiency, immunosuppression or immunosenescence and can present as solitary masses albeit rarely, within the gastrointestinal tract.

Epidemiology and Etiology of Leukemia and Lymphoma

Available evidence suggests that the incidence of leukemia and lymphoma tends to be higher in highly developed regions of the world and among Whites in the United States. Temporal trends in incidence are dynamic and multifactorial; for instance, the incidence of non-Hodgkin's lymphoma increased around the turn of the century, in part because of the acquired immune deficiency syndrome (AIDS) epidemic. Most leukemias and lymphomas are sporadic and the specific etiology remains elusive. Still, research shows that these malignancies often develop in the context of genetic abnormalities, immunosuppression, and exposure to risk factors like ionizing radiation, carcinogenic chemicals, and oncogenic viruses. The prognosis varies by subtype, with poorer survival outcomes for acute leukemias among adults, and more favorable outcomes for Hodgkin's lymphoma. At a time when specific prevention efforts targeting these malignancies are nonexistent, there is a great need to ensure equitable access to diagnostic services and treatments worldwide.

Kaposi Sarcoma in Association With an Extracavitary Primary Effusion Lymphoma Showing Unusual Intravascular Involvement: Report of a Case Harboring a FAM175A Germline Mutation

Primary effusion lymphoma (PEL) is a rare form of aggressive B-cell lymphoma characterized by a malignant serous effusion involving body cavities. It usually associated with human herpes virus-8 (HHV-8) and coexpression of Epstein-Barr virus and mostly affects patients with HIV. We report a rare case of cutaneous PEL with an unusual intravascular presentation, combined with Kaposi sarcoma involving the skin, lung, and gastrointestinal tract. The molecular genetic analysis of the sarcoma and lymphoma components, using next-generation sequencing was performed. The patient was a 67-year-old man who presented with multiple cutaneous tumors and mass in the left lung. He died 17 hours after the admission to the hospital. At autopsy, in addition to the cutaneous lesions, tumors in the left lung and gastrointestinal mucosa were detected, and no effusions in the body cavities were seen. The biopsy from the cutaneous lesions, pulmonary, and intestinal tumors revealed histological and immunohistochemical features of Kaposi sarcoma. In addition, the skin biopsy specimens contained a diffuse infiltrate composed of large pleomorphic cells, with focal intravascular growth that were negative for pan B-cell markers, weakly positive for CD38 and CD138 but expressed CD3, HHV-8, and Epstein-Barr virus. Molecular genetic studies in this specimen revealed monoclonal rearrangements of the IgH gene. The diagnosis of PEL, solid variant, was made. Next-generation sequencing analysis of the tumorous and normal tissue detected a pathogenic germline mutation of the FAM175A gene and somatic mutations in BRCA2 and RAD51B (in both sarcoma and lymphoma specimens), and INPP4B and RICTOR (in lymphoma specimen only).

Serological Assessment of 18 Pathogens and Risk of AIDS-Associated Non-Hodgkin Lymphoma

BACKGROUND

HIV infection is associated with increased susceptibility to common pathogens, which may trigger chronic antigenic stimulation and hyperactivation of B cells, events known to precede the development of AIDS-associated non-Hodgkin lymphoma (AIDS-NHL).

METHODS

To explore whether cumulative exposure to infectious agents contributes to AIDS-NHL risk, we tested sera from 199 AIDS-NHL patients (pre-NHL, average lead time 3.9 years) and 199 matched HIV-infected controls from the Multicenter AIDS Cohort Study, for anti-IgG responses to 18 pathogens using multiplex serology. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models.

RESULTS

We found no association between cumulative exposure to infectious agents and AIDS-NHL risk (OR 1.01, 95% CI: 0.91 to 1.12). However, seropositivity for trichodysplasia spinulosa polyomavirus (TSPyV), defined as presence of antibodies to TSPyV capsid protein VP1, was significantly associated with a 1.6-fold increase in AIDS-NHL risk (OR 1.62, 95% CI: 1.02 to 2.57). High Epstein-Barr virus (EBV) anti-VCA p18 antibody levels closer to the time of AIDS-NHL diagnosis (<4 years) were associated with a 2.6-fold increase in AIDS-NHL risk (OR 2.59, 95% CI: 1.17 to 5.74). In addition, high EBV anti-EBNA-1 and anti-ZEBRA antibody levels were associated with 2.1-fold (OR 0.47, 95% CI: 0.26 to 0.85) and 1.6-fold (OR 0.57, 95% CI: 0.35 to 0.93) decreased risk of AIDS-NHL, respectively.

CONCLUSIONS

Our results do not support the hypothesis that cumulative exposure to infectious agents contributes to AIDS-NHL development. However, the observed associations with respect to TSPyV seropositivity and EBV antigen antibody levels offer additional insights into the pathogenesis of AIDS-NHL.

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.

Human Herpesvirus 8 in Perinatally HIV-infected Children with Interstitial Lung Disease

INTRODUCTION

Human herpesvirus 8 (HHV-8) is associated with the pathogenesis of Kaposi Sarcoma and interstitial pneumonitis in adults. This study aims to evaluate association between HHV-8 and interstitial lung disease in HIV-infected children.

METHODS

HIV-infected children with interstitial pneumonitis underwent lung biopsies in a tertiary hospital and were investigated for HHV-8, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) using polymerase chain reaction (PCR) and immunohistochemistry in lung tissue. Peripheral blood PCR was also performed for HHV-8.

RESULTS

From six patients included, PCR for HHV-8 was positive in lung samples in four children and in peripheral blood in one. PCR for EBV and CMV and immunohistochemical study for HHV-8, EBV and CMV in lung were negative in all patients.

CONCLUSION

No previous cases of HHV-8-associated interstitial pneumonitis was described in HIV-infected children. An immunological disorder and an infectious agent might influence development of the lymphoid interstitial pneumonitis. HHV-8 may be this infectious trigger.

Disseminated Kaposi sarcoma with epithelioid morphology in an HIV/AIDS patient: A previously unreported variant

Kaposi sarcoma is an oligoclonal HHV-8-driven vascular proliferation that was first described by a Viennese dermatologist Dr Moritz Kaposi. The disease has been seen in different clinical-epidemiological settings with a wide morphologic spectrum. We report a 52-year-old Caucasian man with HIV/AIDS and Kaposi sarcoma who presented with dyspnea and pleural effusion. He reported numerous tender subcutaneous nodules developing over the past few months on his chest, back and abdomen. An excisional biopsy of one of the nodules was performed. Touch preps revealed malignant cells in clusters. Microscopically, the neoplasm appeared undifferentiated with an epithelioid morphology, and involved the dermis and subcutaneous fat. Despite the medical history, Kaposi sarcoma was not considered foremost in the differential diagnosis. The malignant cells were positive for vimentin and negative for S100 protein, keratin AE1/3, CK7, CK20, napsin A, TTF-1 and synaptophysin. Additional stains revealed positivity for HHV-8, CD31 and D2-40, supporting the diagnosis of Kaposi sarcoma. Kaposi sarcoma has been well described with many variants that may cause diagnostic difficulty. An epithelioid variant has not been reported and consequently, may cause misinterpretation of an otherwise well-known entity that may become life threatening if appropriate treatment is not initiated in a timely manner.

Human herpesvirus-encoded kinase induces B cell lymphomas in vivo

Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus that is the etiological agent of the endothelial cell cancer Kaposi's sarcoma (KS) and 2 B cell lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). KSHV ORF36, also known as viral protein kinase (vPK), is a viral serine/threonine kinase. We previously reported that KSHV vPK enhances cell proliferation and mimics cellular S6 kinase to phosphorylate ribosomal protein S6, a protein involved in protein synthesis. We created a mouse model to analyze the function of vPK in vivo. We believe this is the first mouse tumor model of a viral kinase encoded by a pathogenic human virus. We observed increased B cell activation in the vPK transgenic mice compared with normal mice. We also found that, over time, vPK transgenic mice developed a B cell hyperproliferative disorder and/or a high-grade B cell non-Hodgkin lymphoma at a greatly increased incidence compared with littermate controls. This mouse model shows that a viral protein kinase is capable of promoting B cell activation and proliferation as well as augmenting lymphomagenesis in vivo and may therefore contribute to the development of viral cancers.

Role of Pattern Recognition Receptors in KSHV Infection

Kaposi’s sarcoma-associated herpesvirus or Human herpesvirus-8 (KSHV/HHV-8), an oncogenic human herpesvirus and the leading cause of cancer in HIV-infected individuals, is a major public health concern with recurring reports of epidemics on a global level. The early detection of KSHV virus and subsequent activation of the antiviral immune response by the host’s immune system are crucial to prevent KSHV infection. The host’s immune system is an evolutionary conserved system that provides the most important line of defense against invading microbial pathogens, including viruses. Viruses are initially detected by the cells of the host innate immune system, which evoke concerted antiviral responses via the secretion of interferons (IFNs) and inflammatory cytokines/chemokines for elimination of the invaders. Type I IFN and cytokine gene expression are regulated by multiple intracellular signaling pathways that are activated by germline-encoded host sensors, i.e., pattern recognition receptors (PRRs) that recognize a conserved set of ligands, known as ‘pathogen-associated molecular patterns (PAMPs)’. On the contrary, persistent and dysregulated signaling of PRRs promotes numerous tumor-causing inflammatory events in various human cancers. Being an integral component of the mammalian innate immune response and due to their constitutive activation in tumor cells, targeting PRRs appears to be an effective strategy for tumor prevention and/or treatment. Cellular PRRs are known to respond to KSHV infection, and KSHV has been shown to be armed with an array of strategies to selectively inhibit cellular PRR-based immune sensing to its benefit. In particular, KSHV has acquired specific immunomodulatory genes to effectively subvert PRR responses during the early stages of primary infection, lytic reactivation and latency, for a successful establishment of a life-long persistent infection. The current review aims to comprehensively summarize the latest advances in our knowledge of role of PRRs in KSHV infections.

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.

Human herpesvirus 8-related diseases: Histopathologic diagnosis and disease mechanisms

The emergence of HIV/AIDS more than three decades ago led to an increased incidence of diseases caused by HHV8 co-infection, particularly Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Over time, the development of highly effective AIDS therapies has resulted in a decreased incidence of HHV8-associated entities, which are now more commonly found in patients with undiagnosed and/or untreated AIDS. Due to their rarity, some of these diseases may be difficult to recognize without appropriate clinical information. This article provides an overview of HHV8-related disorders, with a focus on their morphologic and phenotypic features, and includes a brief overview of laboratory methods used to detect HHV8. Disease mechanisms by which the HHV8 virion promotes tumorigenesis are also reviewed.

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.

KSHV-Mediated Angiogenesis in Tumor Progression

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is a malignant human oncovirus belonging to the gamma herpesvirus family. HHV-8 is closely linked to the pathogenesis of Kaposi's sarcoma (KS) and two other B-cell lymphoproliferative diseases: primary effusion lymphoma (PEL) and a plasmablastic variant of multicentric Castleman's disease (MCD). KS is an invasive tumor of endothelial cells most commonly found in untreated HIV-AIDS or immuno-compromised individuals. KS tumors are highly vascularized and have abnormal, excessive neo-angiogenesis, inflammation, and proliferation of infected endothelial cells. KSHV directly induces angiogenesis in an autocrine and paracrine fashion through a complex interplay of various viral and cellular pro-angiogenic and inflammatory factors. KS is believed to originate due to a combination of KSHV's efficient strategies for evading host immune systems and several pro-angiogenic and pro-inflammatory stimuli. In addition, KSHV infection of endothelial cells produces a wide array of viral oncoproteins with transforming capabilities that regulate multiple host-signaling pathways involved in the activation of angiogenesis. It is likely that the cellular-signaling pathways of angiogenesis and lymph-angiogenesis modulate the rate of tumorigenesis induction by KSHV. This review summarizes the current knowledge on regulating KSHV-mediated angiogenesis by integrating the findings reported thus far on the roles of host and viral genes in oncogenesis, recent developments in cell-culture/animal-model systems, and various anti-angiogenic therapies for treating KSHV-related lymphoproliferative disorders.

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.

Co-infections and Pathogenesis of KSHV-Associated Malignancies

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpes virus 8 (HHV-8) is one of the several carcinogenic viruses that infect humans. KSHV infection has been implicated in the development of Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman’s Disease. While KSHV infection is necessary for the development of KSHV associated malignancies, it is not sufficient to induce tumorigenesis. Evidently, other co-factors are essential for the progression of KSHV induced malignancies. One of the most important co-factors, necessary for the progression of KSHV induced tumors, is immune suppression that frequently arises during co-infection with HIV and also by other immune suppressants. In this mini-review, we discuss the roles of co-infection with HIV and other pathogens on KSHV infection and pathogenesis.

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.

Extracavitary primary effusion lymphoma: clinical, morphological, phenotypic and cytogenetic characterization using nuclei enrichment technique

AIMS

Primary effusion lymphoma (PEL) is a rare form of aggressive B-cell lymphoma, which typically manifests as malignant effusion in the body cavities. However, extracavitary solid variants are also described. The aim of this study was to investigate copy number aberrations in two cases of solid PEL at their first occurrences and relapse by applying a newly developed methodology of tumour nuclei enrichment.

METHODS AND RESULTS

Using histological and genetic techniques, a novel protocol for tumour nuclei enrichment by flow sorting and array-comparative genomic hybridization, we characterized two cases of extracavitary PEL, one of which later relapsed as effusion. Both primary tumours were positive for HHV8 and EBV, confined to lymph nodes, and aberrantly expressed CD3, yet displaying clonal immunoglobulin gene rearrangements indicating B-cell origin. Cytogenetic characterization of primary tumours revealed modest number of aberrations, partially overlapping with previously reported affected loci. The effusional relapse in case 1 was cytogenetically related to the primary tumour but showed dramatic increase of chromosomal instability.

CONCLUSIONS

We for the first time demonstrate a cytogenetic relationship between solid and effusional presentations of PEL. Moreover, we provide an indirect evidence of multiple malignant clones, which gave rise to clonally-related, yet karyotypically different relapsing lymphoma manifestations.

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.

Current concepts in primary effusion lymphoma and other effusion-based lymphomas

Primary effusion lymphoma (PEL) is a human herpes virus 8 (HHV8)-positive large B-cell neoplasm that presents as an effusion with no detectable tumor in individuals with human immunodeficiency virus infection or other immune deficiencies. PEL is an aggressive neoplasm with a poor prognosis. PEL cells show diverse morphologies, ranging from immunoblastic or plasmablastic to anaplastic. The immunophenotype of PEL is distinct, but its lineage can be misdiagnosed if not assessed thoroughly. PEL cells usually express CD45, lack B- and T-cell-associated antigens, and characteristically express lymphocyte activation antigens and plasma cell-associated antigens. Diagnosis of PEL often requires the demonstration of a B-cell genotype. HHV8 must be detected in cells to diagnose PEL. In most cases, PEL cells also harbor the Epstein-Barr virus (EBV) genome. Similar conditions associated with HHV8 but not effusion-based are called "extracavitary PELs." PELs should be differentiated from HHV8-negative, EBV-positive, body cavity-based lymphomas in patients with long-standing chronic inflammation; the latter can occur in tuberculous pleuritis, artificial pneumothorax, chronic liver disease and various other conditions. Despite their morphological similarity, these various lymphomas require different therapeutic strategies and have different prognostic implications. Correct diagnosis is essential to manage and predict the outcome of patients with PEL and related disorders.

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.

Molecular approaches towards characterization, monitoring and targeting of viral-associated hematological malignancies

Viral-associated malignancies usually arise in the setting of altered immunity or with declines in immune function associated with aging. The main culprits are the lymphotropic herpesvirus, including Epstein-Barr virus (EBV) and human herpesvirus-8, which are the focus of this review. Chronic persistent infection and viral reactivation are the main risk factors for development of herpesvirus-associated malignancies and have provided the rationale for intensive monitoring of viral loads in some clinical contexts. Quantitative detection of EBV levels in the post-transplant period and following treatment of EBV-associated malignancies now have a proven role in outcome prediction. Both T-cell immunotherapy and humoral immunotherapies directed against latent viral antigens represent promising interventional approaches to treatment of viral-associated malignancies.

Cytopathologic diagnosis of Kaposi sarcoma in unusual clinical settings

INTRODUCTION

Kaposi sarcoma (KS) is a rare disease that presents as 1 of 4 distinct clinicopathologic subtypes; however, it may present in populations outside those normally encountered. In such cases, it will be important to consider KS in the differential diagnosis, as it may mimic other neoplastic and non-neoplastic entities.

MATERIALS AND METHODS

We describe 2 cases of KS, 1 in a patient not clinically fitting any of the 4 subtypes and the other in a patient with atypical presentation in human immunodeficiency virus (HIV)-associated disease. The first is an 81-year-old African American (AA) woman with a history of KS of the leg, who presented with groin lymphadenopathy and the second is a 42-year-old AA man with a known history of HIV infection, no skin lesions, and new axillary lymphadenopathy.

RESULTS

Fine-needle aspiration of the groin and axillary lymph node, respectively, showed atypical spindle cells in a lymphoplasmacytic background. The spindle cells were positive for human herpesvirus-8 on the cell block and subsequent lymph node excision. In patients with HIV infection, in addition to reactive and lymphoproliferative processes, KS should be considered. In the former case, the demographic of an elderly AA woman without immunosuppression would not cause concern for systemic KS, but for a metastatic tumor or lymphoma.

CONCLUSIONS

Cytology is a helpful tool in narrowing the differential diagnosis for spindle cell lesions. With a diagnosis of KS, clinicians would be able to query the clinical history for a possible etiology, such as HIV, and exclude the possibility of metastatic disease.

Cutaneous plasmablastic lymphoma in an immunocompetent patient with long-term pyrimethamine use for essential thrombocythemia: a case report and literature review

We report a case of Epstein-Barr-virus-(EBV-) positive primary cutaneous plasmablastic lymphoma in a human-immunodeficiency-virus-(HIV-) negative, immunocompetent 62-year-old female patient. We postulate that her lymphoma development is due to the longstanding use of pyrimethamine for essential thrombocythemia. This has never been described in the literature.

Plasmablastic lymphoma of the small intestine: Case report and literature review

Plasmablastic lymphoma (PBL) is a rare aggressive B-cell lymphoproliferative disorder, which has been characterized by the World Health Organization as a new entity. Although PBL is most commonly seen in the oral cavity of human immunodeficiency virus (HIV)-positive patients, it can also be seen in extra-oral sites in immunocompromised patients who are HIV-negative. Here we present a rare case of PBL of the small intestine in a 55-year-old HIV-negative male. Histopathological examination of the excisional lesion showed a large cell lymphoma with plasmacytic differentiation diffusely infiltrating the small intestine and involving the surrounding organs. The neoplastic cells were diffusely positive for CD79a, CD138 and CD10 and partly positive for CD38 and epithelial membrane antigen. Approximately 80% of the tumor cells were positive for Ki-67. A monoclonal rearrangement of the kappa light chain gene was demonstrated. The patient died approximately 1.5 mo after diagnosis in spite of receiving two courses of the CHOP chemotherapy regimen. In a review of the literature, this is the first case report of PBL with initial presentation in the small intestine without HIV and Epstein-Barr virus infection, and a history of hepatitis B virus infection and radiotherapy probably led to the iatrogenic immunocompromised state.

Macaque homologs of EBV and KSHV show uniquely different associations with simian AIDS-related lymphomas

Two gammaherpesviruses, Epstein-Barr virus (EBV) (Lymphocryptovirus genus) and Kaposi's sarcoma-associated herpesvirus (KSHV) (Rhadinovirus genus) have been implicated in the etiology of AIDS-associated lymphomas. Homologs of these viruses have been identified in macaques and other non-human primates. In order to assess the association of these viruses with non-human primate disease, archived lymphoma samples were screened for the presence of macaque lymphocryptovirus (LCV) homologs of EBV, and macaque rhadinoviruses belonging to the RV1 lineage of KSHV homologs or the more distant RV2 lineage of Old World primate rhadinoviruses. Viral loads were determined by QPCR and infected cells were identified by immunolabeling for different viral proteins. The lymphomas segregated into three groups. The first group (n = 6) was associated with SIV/SHIV infections, contained high levels of LCV (1–25 genomes/cell) and expressed the B-cell antigens CD20 or BLA.36. A strong EBNA-2 signal was detected in the nuclei of the neoplastic cells in one of the LCV-high lymphomas, indicative of a type III latency stage. None of the lymphomas in this group stained for the LCV viral capsid antigen (VCA) lytic marker. The second group (n = 5) was associated with D-type simian retrovirus-2 (SRV-2) infections, contained high levels of RV2 rhadinovirus (9–790 genomes/cell) and expressed the CD3 T-cell marker. The third group (n = 3) was associated with SIV/SHIV infections, contained high levels of RV2 rhadinovirus (2–260 genomes/cell) and was negative for both CD20 and CD3. In both the CD3-positive and CD3/CD20-negative lymphomas, the neoplastic cells stained strongly for markers of RV2 lytic replication. None of the lymphomas had detectable levels of retroperitoneal fibromatosis herpesvirus (RFHV), the macaque RV1 homolog of KSHV. Our data suggest etiological roles for both lymphocryptoviruses and RV2 rhadinoviruses in the development of simian AIDS-associated lymphomas and indicate that the virus-infected neoplastic lymphoid cells are derived from different lymphocyte lineages and differentiation stages.

The incidence of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma increased in conjunction with the epidemic of HIV disease and AIDS. These malignancies are now known to be associated with secondary infections with a gammaherpesvirus; KS, with the Kaposi's sarcoma-associated herpesvirus (KSHV) and lymphoma, with both KSHV and Epstein-Barr virus (EBV). Similar AIDS-related malignancies have been observed in monkeys with simian AIDS and monkey gammaherpesviruses related to KSHV and EBV have been implicated in the development of disease. The study of monkey models of AIDS-related malignancies provides important approaches for understanding the role of gammaherpesviruses in AIDS-related tumorigenesis. Here we have used a combined molecular and immunological approach to identify, quantitate and localize infections of gammaherpesviruses in AIDS-associated lymphomas in macaques. We found high levels of macaque viruses related to EBV and KSHV in the tumor cells of distinct types of macaque lymphomas, suggesting that the virus-infected tumor cells belong to different lymphocyte lineages and differentiation stages.

Plasmablastic lymphoma in pediatric patients: clinicopathologic study of three cases

Plasmablastic lymphoma (PBL) is an aggressive high grade non-Hodgkin lymphoma which occurs predominantly in adult patients who are concomitantly afflicted with HIV infection. In contrast to several reports and studies of PBL in adult patients, PBL has very rarely been reported in pediatric patients. This article hereby provides collaborative clinicopathologic information of de novo PBL diagnosed in 3 pediatric patients with concomitant HIV infection. Cognizance of this rare tumor in the pediatric population coupled with antiretroviral therapy and prompt initiation of multimodality treatment may, in the future, facilitate improved outcome in pediatric patients with PBL.

Treatment of Kaposi sarcoma-associated herpesvirus-associated cancers

Kaposi sarcoma (KS) is the most frequent AIDS-defining cancer worldwide. KS-associated herpesvirus (KSHV) is the etiological agent of KS, and the virus is also associated with two lymphoproliferative diseases. Both KS and KSHV-associated lymphomas, are cancers of unique molecular composition. They represent a challenge for cancer treatment and an opportunity to identify new mechanisms of transformation. Here, we review the current clinical insights into KSHV-associated cancers and discuss scientific insights into the pathobiology of KS, primary effusion lymphoma, and multicentric Castleman's disease.

Extracavitary/solid variant of primary effusion lymphoma

Primary effusion lymphoma (PEL) is a distinct clinicopathologic entity associated with human herpesvirus 8 (HHV8) infection that mostly affects patients with immunodeficiency. Primary effusion lymphoma usually presents as a malignant effusion involving the pleural, peritoneal, and/or pericardial cavities without a tumor mass. Rare cases of HHV8-positive lymphoma with features similar to PEL can present as tumor masses in the absence of cavity effusions and are considered to represent an extracavitary or solid variant of PEL. Here, we report 3 cases of extracavitary PEL arising in human immunodeficiency virus-infected men. Two patients had lymphadenopathy and underwent lymph node biopsy. One patient had a mass involving the ileum and ascending colon. In lymph nodes, the tumor was predominantly sinusoidal. The tumor involving the ileum and ascending colon presented as 2 masses, 12.5 × 10.6 × 2.6 cm in the colon and 3.6 × 2.7 × 1.9 cm in the ileum. In each case, the neoplasms were composed of large anaplastic cells, and 2 cases had "hallmark cells." Immunohistochemistry showed that all cases were positive for HHV8 and CD138. One case also expressed CD4 and CD30, and 1 case was positive for Epstein-Barr virus-encoded RNA. Evidence of B-cell differentiation was poorly developed in all tumors. These cases highlight the importance of assessing HHV8 in an anaplastic tumor that arises in a human immunodeficiency virus-positive patient and further contributes to the limited literature currently available for extracavitary PEL.

Plasmablastic lymphoma of the cecum: report of a case with cytologic findings

Plasmablastic lymphoma (PBL) is a rare lymphoma that is characterized by a diffuse proliferation of large neoplastic cells resembling B immunoblasts, but shows the immunophenotype of plasma cells. PBL is most commonly seen in the oral cavity of human immunodeficiency virus (HIV)-positive patients. Epstein-Barr virus (EBV) may be closely related the pathogenesis of PBL. We report a case of HIV-negative PBL in a 75-year-old man without EBV infection. Histologic examination of the cecal tumor following right hemicolectomy and cytologic examination of ascitic fluid were performed. Cytologic specimens were hypercellular and composed of single cells and loosely formed clusters. Large tumor cells showed plasmacytoid features with basophilic cytoplasm, large nuclei, prominent nucleoli, and focal perinuclear halos. Abnormal mitotic figures were easily identified. On immunohistologic study, the tumor cells were positive for CD138 (plasma cell marker) and kappa, but negative for CD45, CD3, CD20, CD79a, CD56, and cyclin D1. The proliferation index (Ki-67) was high. This is a very rare case of PBL without HIV and EBV infection, involving the cecum.

Castleman's disease: systematic analysis of 416 patients from the literature

BACKGROUND

Castleman's disease is a rare primary disease of the lymph nodes with limited available clinical information.

METHODS

A systematic literature search identified 416 cases amenable to detailed analysis.

RESULTS

In HIV(-) patients, centricity, pathology type, the presence of symptoms, gender, and age all predict outcome in univariate analyses. The 3-year disease-free survival (DFS) rate for patients with unicentric hyaline vascular disease (49.5% of cases, class I) was 92.5%, versus 45.7% for those with multicentric plasma cell disease (20.2% of cases, class III) and 78.0% for those with any other combination (22.6% of cases, class II) (p < .0001). HIV(+) patients (class IV) exclusively presented with multicentric plasma cell disease and had a 3-year DFS rate of only 27.8%. Kaposi's sarcoma and lymphoma were observed in 59.3% and 9.4% of HIV(+) patients and in 2.6% and 3.6% of HIV(-) patients (p < .0001). Paraneoplastic pemphigus and the syndrome of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes were observed exclusively in HIV(-) patients at a rate of 1.3% and 1.8%, respectively.

CONCLUSION

Clinical, pathological, and viral markers allow for the classification of Castleman's disease into groups with markedly different outcomes and disease associations.

Primary leptomeningeal plasmablastic lymphoma

Lymphomas that develop in human immunodeficiency virus (HIV) infected patients are predominantly aggressive B-cells lymphomas. The most common HIV-associated lymphomas include Burkitt lymphoma, diffuse large B-cell lymphoma (that often involves the CNS), primary effusion lymphoma, and plasmablastic lymphoma (PBL). Of these, PBL is relatively uncommon and displays a distinct affinity for presentation in the oral cavity. In this manuscript we report a previously undescribed primary leptomeningeal form of PBL in a patient with acquired immunodeficiency syndrome. A 40-year-old HIV positive man presented with acute onset confusion, emesis, and altered mental status. Lumbar puncture showed numerous nucleated cells with atypical plasmocyte predominance. CSF flowcytometry showed kappa restriction with CD8 and CD38 positivity and negative lymphocyte markers, while the MRI showed diffuse leptomeningeal enhancement. As the extensive systemic work-up failed to reveal any disease outside the brain, an en bloc diagnostic brain and meningeal biopsy was performed. The biopsy specimen showed sheets of plasmacytoid cells with one or more large nuclei, prominent nuclear chromatin, scattered mitoses, and abundant cytoplasm, highly suggestive of plasmablastic lymphoma. HIV-associated malignancies have protean and often confusing presentations, which pose diagnostic difficulties posed to the practicing neurological-surgeons. Even in cases where an infectious cause is suspected for the meningeal enhancement, neoplastic involvement should be considered, and cytology and flow-cytometry should be routinely ordered on the CSF samples.

NF-κB as a target for oncogenic viruses

NF-κB is a pivotal transcription factor that controls cell survival and proliferation in diverse physiological processes. The activity of NF-κB is tightly controlled through its cytoplasmic sequestration by specific inhibitors, IκBs. Various cellular stimuli induce the activation of an IκB kinase, which phosphorylates IκBs and triggers their proteasomal degradation, causing nuclear translocation of activated NF-κB. Under normal conditions, the activation of NF-κB occurs transiently, thus ensuring rapid but temporary induction of target genes. Deregulated NF-κB activation contributes to the development of various diseases, including cancers and immunological disorders. Accumulated studies demonstrate that the NF-κB signaling pathway is a target of several human oncogenic viruses, including the human T cell leukemia virus type 1, the Kaposi sarcoma-associated herpesvirus, and the Epstein-Bar virus. These viruses encode specific oncoproteins that target different signaling components of the NF-κB pathway, leading to persistent activation of NF-κB. This chapter will discuss the molecular mechanisms by which NF-κB is activated by the viral oncoproteins.

Herpesvirus-Associated B-cell Proliferations

This article reviews the spectrum of Epstein-Barr virus and Kaposi sarcoma herpesvirus (KSHV/HHV-8)-associated B-cell lymphoid proliferations, their pathologic features and clinical presentation, diagnostic criteria, and pathogenetic aspects. Emphasis is on the differential diagnosis issues and difficulties that the pathologist may face for the correct identification and interpretation of these lesions.

Oral and extraoral plasmablastic lymphoma: similarities and differences in clinicopathologic characteristics

Plasmablastic lymphoma (PBL), initially characterized as an aggressive lymphoma arising in the jaw and oral mucosa in HIV-infected patients, was recently reported to occur with extraoral manifestations, heterogeneous histologic findings, and variable association with immunodeficiency states. We reviewed clinical, morphologic, and immunophenotypic features of 13 cases of PBL to determine whether these different subtypes represent distinct morphologic and clinical entities. Two distinct subtypes of PBL were identified and classified as oral and extraoral PBL. The oral PBLs were strongly associated with HIV infection and commonly demonstrated plasmablastic morphologic features without plasmacytic differentiation. Extraoral PBLs tended to occur in patients with underlying non-HIV-related immunosuppression and universally demonstrated plasmacytic differentiation. The patients with oral PBL demonstrated better overall survival compared with patients with extraoral PBL (P = .02). Our findings suggest that PBL with oral and extraoral manifestation represent 2 distinct clinicopathologic entities.

Castleman's disease--a two compartment model of HHV8 infection

Castleman's disease is a primary infectious disease of the lymph node that causes local symptoms or a systemic inflammatory syndrome. Histopathology reveals a destroyed lymph node architecture that can range from hyaline-vascular disease to plasma-cell disease. Viral interleukin 6 (vIL-6) produced during the replication of human herpesvirus type 8 (HHV8) is the key driver of systemic inflammation and cellular proliferation. Stage progression of Castleman's disease results from switches between viral latency and lytic replication, and lymphatic and hematogenous spread. Multicentric plasma-cell disease in HIV-1 patients is associated with HHV8 infection. Polyclonal plasmablast proliferation escapes control in the germinal center with eventual malignant transformation into non-Hodgkin lymphoma. Surgery produces excellent results in unicentric disease, while multicentric disease responds to anti-CD20 therapy or IL-6 and chemotherapy. Lymphovascular endothelium and naive B cells are infectious reservoir-opening options for antiangiogenic and anti-CD19 strategies to enhance outcomes in patients with systemic disease.

Incidence and risk factors of HIV-related non-Hodgkin's lymphoma in the era of combination antiretroviral therapy: a European multicohort study

BACKGROUND

Incidence and risk factors of HIV-associated non-Hodgkin's lymphoma (NHL) are not well defined in the era of combination antiretroviral therapy (cART).

METHODS

A total of 56,305 adult HIV type-1 (HIV-1)-infected patients who started cART in 1 of 22 prospective studies in Europe were included. Weibull random effects models were used to estimate hazard ratios (HRs) for developing systemic NHL and included CD4(+) T-cell counts and viral load as time-updated variables.

RESULTS

During the 212,042 person-years of follow-up, 521 patients were diagnosed with systemic NHL and 62 with primary brain lymphoma (PBL). The incidence rate of systemic NHL was 463 per 100,000 person-years not on cART and 205 per 100,000 person-years in treated patients for a rate ratio of 0.44 (95% confidence interval [CI] 0.37-0.53). The corresponding incidence rates of PBL were 57 and 24 per 100,000 person-years (rate ratio 0.43, 95% CI 0.25-0.73). Suppression of HIV-1 replication on cART (HR 0.60, 95% CI 0.44-0.81, comparing < or =500 with 10,000-99,999 copies/ml) and increases in CD4(+) T-cell counts (HR 0.30, 0.22-0.42, comparing > or =350 with 100-199 cells/microl) were protective; a history of Kaposi's sarcoma (HR 1.70, 1.08-2.68, compared to no history of AIDS), transmission through sex between men (HR 1.57, 1.19-2.08, compared with heterosexual transmission) and older age (HR 3.71, 2.37-5.80, comparing > or =50 with 16-29 years) were risk factors for systemic NHL.

CONCLUSIONS

The incidence rates of both systemic NHL and PBL were substantially reduced in patients on cART. Timely initiation of therapy is key to the prevention of NHL in the era of cART.

EBV and HIV-Related Lymphoma

HIV-associated lymphoproliferative disorders represent a heterogeneous group of diseases, arising in the presence of HIV-associated immunodeficiency. The overall prevalence of HIV-associated lymphoma is significantly higher compared to that of the general population and it continues to be relevant even after the wide availability of highly active antiretroviral therapy (HAART) (1). Moreover, they still represent one of the most frequent cause of death in HIV-infected patients. Epstein-Barr virus (EBV), a γ-Herpesviruses, is involved in human lymphomagenesis, particularly in HIV immunocompromised patients. It has been largely implicated in the development of B-cell lymphoproliferative disorders as Burkitt lymphoma (BL), Hodgkin disease (HD), systemic non Hodgkin lymphoma (NHL), primary central nervous system lymphoma (PCNSL), nasopharyngeal carcinoma (NC). Virus-associated lymphomas are becoming of significant concern for the mortality of long-lived HIV immunocompromised patients, and therefore, research of advanced strategies for AIDS-related lymphomas is an important field in cancer chemotherapy. Detailed understanding of the EBV lifecycle and related cancers at the molecular level is required for novel strategies of molecular-targeted cancer chemotherapy The linkage of HIV-related lymphoma with EBV infection of the tumor clone has several pathogenetic, prognostic and possibly therapeutic implications which are reviewed herein.

HHV8-positive, EBV-positive Hodgkin lymphoma-like large B-cell lymphoma and HHV8-positive intravascular large B-cell lymphoma

Human herpesvirus type 8 (HHV8), also known as Kaposi's sarcoma-associated herpesvirus, is a human gamma herpesvirus that underlies the pathogenesis of Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. We recently encountered two cases of HHV8-positive large B-cell lymphoma with features not previously described. The first patient was a 61-year-old immunocompetent man with an enlarged cervical lymph node containing scattered large, bizarre cells in a reactive background of lymphocytes, plasma cells and scattered regressed follicles resembling those of hyaline-vascular Castleman's disease. The appearance suggested classical Hodgkin's lymphoma, but the large cells were negative for CD15, CD30, CD20 and CD3, and positive for MUM1/IRF4, EMA, HHV8, EBER and dim IgM lambda. The second patient was a 59-year-old HIV-positive man who died after several weeks of fever, night sweats, anemia, thrombocytopenia, hepatosplenomegaly and multiorgan failure. At autopsy an intravascular large B-cell lymphoma that was positive for MUM1/IRF4, HHV8 and IgM lambda, and negative for CD20 and EBER involved multiple organs, including lung, heart, kidney, liver and spleen. On the basis of the histologic features in these two cases, the presence of HHV8 was unexpected. These cases expand the spectrum of lymphoproliferative disorders that can be associated with HHV8.

Plasmablastic lymphoma: a review

Plasmablastic lymphoma (PBL) has been recently characterised as an aggressive subtype of non-Hodgkin's lymphoma, most frequently arising in the oral cavity of HIV-infected patients. To date, approximately 60 cases fulfilling the clinico-pathological characteristics of PBL have been reported. PBLs are composed of large cells with eccentrically located nuclei and deeply basophilic cytoplasm with a paranuclear hof. The tumour cells are invariably immunoreactive for the plasma cell marker CD138, and show monoclonal rearrangement of the immunoglobulin heavy chain gene (IgH) and/or clonal restriction of the Ig light chain (IgL) gene expression in most of the cases. Similar to other types of AIDS-related lymphomas, there is evidence that Epstein-Barr virus and Kaposi-sarcoma associated Human Herpes Virus 8 may play a relevant role in the pathogenesis of PBL. PBL patients have been treated heterogeneously, with a combination of chemotherapy, radiotherapy and/or surgery, and their prognosis is usually poor, with a death rate of approximately 60% at 1 year.

HIV-associated plasmablastic lymphoma: lessons learned from 112 published cases

Plasmablastic lymphoma (PBL) is a distinct subtype of non-Hodgkin B-cell lymphoma, originally described with a strong predilection to the oral cavity of human immunodeficiency virus (HIV)-infected individuals. Data regarding patient age and gender, HIV status, initiation of and response to highly active antiretroviral therapy (HAART), tumor extent, pathology, treatment, and outcome were extracted from 112 cases of PBL identified in the literature. The median age at presentation was 38 years with a male predominance of 7:1, and the median CD4+ count was 178 cells/mm(3). PBL presented on average 5 years after diagnosis of HIV. Common primary sites of presentation included the oral cavity, gastrointestinal tract, and lymph nodes. Most cases presented with either stage I or stage IV disease. There was a variable expression of B-cell markers in tumor cells, but plasma cell markers were expressed in all cases. EBV was detected in 74%. Chemotherapy was used to treat 55% patients and was combined with radiotherapy in 21% cases. Complete response was obtained in 66% of treated cases; the majority of these responses were seen after CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). The refractory/relapsed disease rate was 54%. Death occurred in 53% of patients, with a median overall survival of 15 months. Sex, CD4+ count, viral load, clinical stage, EBV status, primary site of involvement, and use of CHOP failed to show an association with survival. PBL is an aggressive B-cell lymphoma that presents in both oral and extra-oral sites of chronically HIV-infected immunosuppressed young men.