EBV-Associated Lymphoproliferative Disorders: Update in Classification.

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

Acute Epstein-Barr virus-positive cytotoxic T cell lymphoid hyperplasia in the upper aerodigestive tract, mimicking extranodal natural killer/T cell lymphoma, nasal type.

To describe the clinicopathological features of nine patients with acute Epstein-Barr virus (EBV)-positive cytotoxic T cell lymphoid hyperplasia (EBV+TLH) in the upper aerodigestive tract, in which initial findings led to a preliminary misdiagnosis of extranodal NK/T cell lymphoma, nasal type (ENKTL). A series of nine cases of EBV+TLH in one Chinese institution over a 9-year interval was retrospectively analyzed. Median age was 16 years (range 5-29 years) with a M:F ratio of 5:4. All patients were previously healthy with an acute onset period of < 1 month. Six patients (66%) presented with masses or polypoid protrusions in the upper aerodigestive tract. Nasopharyngeal symptoms, cervical lymphadenopathy, and fever were found in 89%, 78%, and 56% of patients, respectively. In seven cases, morphology mainly showed small-sized irregular cells and in two cases medium-to-large cells. In all cases, the cells diffusely expressed cytoplasmic CD3 and at least one marker for cytotoxic granules, but were negative for CD56. CD5 expression was detected in eight cases (8/9, 89%). In all cases, double staining for CD3 and EBER indicated that most T cells were infected with EBV. T cell receptor gene rearrangement was performed in five cases and all showed polyclonal results. All patients achieved complete remission within 1 month after diagnosis without any chemoradiotherapy and were followed up 19-124 months without recurrent disease. EBV+TLH in the upper aerodigestive tract is occasionally observed in China. The histopathologic features of EBV+TLH can mimic ENKTL. EBV+TLH should be taken into consideration as a potential diagnosis when the disease duration is short, spontaneous remission is achieved without intervention, and when histology shows infiltration with EBV-infected T lymphocytes.

Hepatic Pseudolymphoma with an Occult Hepatitis B Virus Infection.

A 49-year-old woman who was asymptomatic was found to have a small liver tumor on abdominal ultrasonography (US) at her annual health checkup. US revealed a hypoechoic, solid, mass measuring 17-mm in size in segment 6. The tumor markers associated with liver malignancy were negative. An infectious disease screen was negative for hepatitis B surface antigen, but positive for antibody to hepatitis B core antigen. Imaging studies using computed tomography (CT), magnetic resonance imaging (MRI), and CT angiography suggested a malignant liver tumor, such as hepatocellular carcinoma. Partial hepatic resection of the posterior segment was performed. The pathological diagnosis was pseudolymphoma of the liver.

A novel avian retrovirus associated with lymphocytoma isolated from a local Chinese flock induced significantly reduced growth and immune suppression in SPF chickens.

Avian Leukosis Viruses (ALVs) are associated with neoplasias, immune suppression and reduced performance in chicken flocks. In the present study, a naturally occurring recombinant strain of ALV (FJ15HT0) was isolated from an infected flock of Chinese "Hetian" chickens, and was subsequently identified as an exogenous ALV by immuno-fluorescence assay (IFA), PCR and following entire proviral DNA nucleotide sequencing. This isolate is revealed as a novel recombinant virus, lacking viral oncogenes, with the gp85 (93.4%) of subgroup B, the U3 (92.1%) and R (95.2%) region of subgroup J, the U5 (93.8%) region and 5'UTR (95.7%) of subgroup C, as well as the gp37 (90.6%) and 3' (92.2%) of ALV-E. The simulative congenital infection with this isolate in SPF chickens resulted in significant weight loss (P<0.05) and a significant reduction in the humoral immune response to the live NDV vaccine (P<0.05), but not to the inactive AIV-H5 vaccine (P>0.05). Foci of lymphocytomas were observed in tissues of congenitally infected chickens at 11 weeks post-hatch, demonstrating the acute oncogenicity of the isolate.

Incidental EBV-positivity in paediatric post-transplant specimens demonstrates the need for stringent criteria for diagnosing post-transplant lymphoproliferative disorders.

AIMS: To examine the need for minimal diagnostic criteria for post-transplant lymphoproliferative disorders (PTLD) in children, we sought to determine the rate of incidental Epstein-Barr virus (EBV)-positivity in tissues from organ transplant recipients (OTR). METHODS: EBV in situ hybridisation (ISH) was done retrospectively on tissue from 34 paediatric autopsies of OTR and paediatric tonsillectomy specimens from non-OTR (96) and OTR (6). Patients with a history of PTLD were excluded from both data sets. RESULTS: EBV-positivity was found incidentally in 2/34 autopsy cases (5.9%). Median time from transplant to death for all patients was 12.8 months (range 0.1-153 months). Median time between transplant and death in EBV-positive cases was 34 months. EBV was positive in 26/102 tonsils (25%). Among tonsils from OTR, 4/6 (67%) were EBV-positive. CONCLUSIONS: These findings reinforce the need for strict morphological and clinical criteria, other than EBV-positivity, when diagnosing PTLD in the paediatric population.

The comparison of the pathological data of oropharyngeal masses between HIV and non-HIV patients.

CONCLUSION: Although this study did not show higher risk of oropharyngeal malignancy in HIV patients overall, they still had much higher prevalence of NHL as well as HL than HIV negative patients. Presence of cervical lymphadenopathy is unreliable in differentiating malignant oropharyngeal tumours from benign lymphoid hyperplasia in HIV patients. OBJECTIVES: The aim of this study was to compare the histology of oropharyngeal masses between HIV positive and negative patients. METHODS: A retrospective review of 119 patients who underwent oropharyngeal biopsies in a tertiary institution between 2007-2014 and whose HIV status was known (HIV positives =47; negatives =72). RESULTS: Malignancies occurred in 63.8% of HIV patients and 65% of the negative group (p = 0.87). While non-Hodgkin's lymphoma (NHL), squamous cell carcinoma (SCC), and Hodgkin's lymphoma (HL) constituted 40%, 27%, and 17% of malignancies in HIV patients, respectively; in the HIV-negative group, it was 53%, 13%, and 2% for SCC, NHL, and HL, respectively (p = 0.039, 0.017, and 0.035, respectively). Reactive lymphoid proliferation accounted for 82.4% of the benign masses in the HIV positive group. Malignant tumours were recorded more in younger patient in the HIV positive than the negative group (p = 0.001).

Sonographic distinction between acute suppurative appendicitis and viral appendiceal lymphoid hyperplasia ("pink appendix") with pathological correlation.

The viral etiology of mesenteric lymphadenitis may also affect the lymphoid tissue of the appendix in children giving rise to symptomatic appendiceal lymphoid hyperplasia, the so-called "pink appendix." The present study used ultrasound (US) to determine if certain sonographic features correlated with appendiceal pathological findings. Our results indicate that a fluid-filled appendix always correlates with a suppurative or mixed pathological appearance that likely merits surgery. A lymphoid predominant pathological appearance occurred only in cases where appendiceal wall thickening alone was seen on US. This pilot project therefore shows that US has the potential to stratify acute appendix patients into different treatment regimens, given that lymphoid hyperplasia could be treated conservatively. Further studies correlating other clinicoradiological parameters with this sonographic appearance are warranted.

Epstein-Barr virus, the germinal centre and the development of Hodgkin's lymphoma.

The relationship between Epstein-Barr virus (EBV) and the germinal centre (GC) of the asymptomatic host remains an enigma. The occasional appearance of EBV-positive germinal centres in some patients, particularly those with a history of immunosuppression, suggests that EBV numbers in the GC are subject to immune control. The relationship, if any, between lymphoid hyperplasia with EBV-positive germinal centres and subsequent or concurrent lymphomagenesis remains to be clarified. As far as the development of EBV-associated Hodgkin's lymphoma is concerned, the suppression of virus replication, mediated by LMP1 on the one hand, and the loss of B-cell receptor signalling on the other, appears to be an important pathogenic mechanism. A further important emerging concept is that alterations in the microenvironment of the EBV-infected B-cell may be important for lymphomagenesis.

[Epstein-Barr virus infection and expression of latent membrane protein 2A in Hodgkin's lymphoma of Uygur patients].

OBJECTIVE: To investigate Epstein-Barr virus(EBV) infection in Hodgkin's lymphoma (HL) of Uygur patients and related clinicopathological characteristics. METHODS: EBV-encoded small RNA (EBER) was detected in 40 cases of HL and 20 cases of lymphoid reactive hyperplasia by in-situ hybridization. Expression of LMP2A in HL was investigated by immunohistochemistry. RESULTS: EBV was detected in 26/40 (65.0%) of HL and 5/20 of lymphoid reactive hyperplasia (P < 0.05). The expression level of EBER showed significant difference among various histological subtypes of HL (P < 0.05) and between patients with and without B symptom (P = 0.02). However, no difference was found in relation to gender, clinical stage and tumor burden. The expression of LMP2A in the mixed cellularity and nodular sclerosis classical HL associated with EBV infection was 57.7% (15/26). Expression of LMP2A was not detected in lymphoid reactive hyperplasia cases. CONCLUSION: Uyghur patients with Hodgkin's lymphoma have a high infection rate of EBV and distinct clinicopathologic characteristics.

Age-related EBV-associated lymphoproliferative disorders in the Western population: a spectrum of reactive lymphoid hyperplasia and lymphoma.

We investigated age-related EBV(+) B-cell lymphoproliferations in the Western population. The clinical features, histology, immunophenotype, EBV-encoded RNA in situ hybridization, and clonality by PCR of T-cell receptor gamma and immunoglobulin genes were categorized in 122 EBV(+) lesions as follows: (1) reactive lymphoid hyperplasia; (2) polymorphic extranodal or (3) polymorphic nodal lymphoproliferative disease (LPD); and (4) diffuse large B-cell lymphoma (DLBCL). Interphase FISH for IG and PAX5 gene rearrangements was performed on 17 cases of DLBCL. The overall median age was 75 years (range, 45-101 years; 67 men, 55 women), and 67, 79, 73, and 77 years, respectively, for groups 1 through 4. Sixteen of 21 cases of polymorphic extranodal LPD were classified as EBV(+) mucocutaneous ulcer. PCR for immunoglobulin genes was polyclonal in reactive lymphoid hyperplasia (84%) and monoclonal in 33%, 63%, and 56% of polymorphic extranodal and nodal LPD cases and DLBCL, respectively. All groups showed restricted/clonal T-cell receptor responses (27%-70%). By FISH, 19% of DLBCLs showed IGH@ rearrangements, but PAX5 was unaffected. Disease-specific 5-year survival was 100%, 93%, 57%, and 25% for groups 1-4, respectively, and 100% for patients with EBV(+) mucocutaneous ulcer. Disease volume was predictive of therapy response (P = .0002), and pathologic subtype was predictive of overall outcome (P = .001). Age-related EBV(+) B-cell LPD encompasses a wider disease spectrum than previously recognized and includes both reactive and neoplastic conditions. Reduction in the T-cell repertoire may contribute to decreased immune surveillance.

Prevalence of Merkel cell polyomavirus DNA in cutaneous lymphomas, pseudolymphomas, and inflammatory skin diseases.

Several groups confirmed Merkel cell polyomavirus (MCPyV) as the likely causative agent of Merkel cell carcinoma. Hematolymphoid disorders are known to be a substantial risk factor for Merkel cell carcinoma, and vice versa. The association between MCPyV and hematologic neoplasms is poorly analyzed, as well as the speculation that lymphocytes may serve as reservoir for MCPyV. Therefore, we investigated the prevalence of MCPyV DNA in primary cutaneous T- and B-cell lymphomas, pseudolymphomas (PLs), and inflammatory skin diseases with dominant lymphocytic infiltrate. We performed a molecular pathology study in 22 tissue samples and 1 blood sample of different cutaneous lymphomas from 19 patients (17 mature T-cell neoplasms, 5 mature B-cell neoplasms, and 1 immature hematopoietic malignancy), 13 PLs from 12 patients, and 25 various inflammatory skin diseases from 23 patients. All tumors were analyzed for the presence of MCPyV DNA by polymerase chain reaction, confirmed by Southern blot hybridization of polymerase chain reaction products. We detected MCPyV DNA in 4 of 23 (17.4%) cutaneous lymphoma tissue samples (3 of 17 mature T-cell neoplasms and 1 of 5 mature B-cell neoplasms), in 2 of 13 (15.4%) PL tissue samples, and 2 of 25 (8%) inflammatory skin conditions (1 drug reaction and 1 erythema multiforme). We conclude that MCPyV DNA is infrequently, but consistently present in lesional tissue from patients with primary cutaneous lymphomas, PLs, and inflammatory skin diseases; prevalence is in the range of 8%-17%. Our results suggest that MCPyV does not play a significant role in the pathogenesis of cutaneous lymphoproliferative disorders.

[Correlation of Epstein-Barr virus infection and childhood lymphoma].

OBJECTIVE: To investigate the correlation of Epstein-Barr virus (EBV) infection and childhood lymphoma. METHODS: Paraffin-embedded specimens of lymphoma collected between 1996 and 2005, including 36 Hodgkin lymphomas (HL) and 51 non-Hodgkin lymphomas (NHL), were included in this study. Paraffin-embedded specimens of reactive hyperplasia of lymph nodes (RL) collected during the same period were used as controls. Immunohistochemical (IHC) assay was used to detect EBV-LMP1 and in situ hybridization (ISH) to detect EBV-EBERs. RESULTS: EBV was detected in 72.2% (26/36) of the Hodgkin lymphomas, 15.7% (8/51) of the non-Hodgkin lymphomas and 33.3% (15/45) of the reactive hyperplasia of lymph nodes. There was a significant difference among Hodgkin lymphoma, non-Hodgkin lymphoma and RL (P = 0. 000). CONCLUSION: Childhood Hodgkin lymphoma is closely correlated with Epstein-Barr virus infection. However, the low rate of EBV infection detected in childhood non-Hodgkin lymphoma might be due to heterogeneous distribution of pathological types in this study.

Adenoviral appendicitis presenting clinically as acute appendicitis.

The vermiform appendix may react as part of a generalized viral infection, but histological documentation of appendiceal viral infection is rare. Adenovirus has been described in association with mesenteric adenitis and ileocecal intussusception, but to our knowledge there are no well-documented cases of adenoviral appendiceal infection presenting clinically as acute appendicitis without intussusception. We reviewed the pathology records of all appendectomies performed at our institution from 2001 through 2005. All incidental appendectomies and appendices with acute appendicitis or other pathological findings were excluded. We selected all negative appendices with lymphoid hyperplasia and reviewed hematoxylin and eosin-stained slides. Representative sections of each of these cases were immunostained with adenovirus antibody. Eight hundred seventy-seven appendectomies were performed during the study period. Of these, there were 94 cases that had a clinical diagnosis of acute appendicitis and that were pathologically negative. Sixty-three of the 94 cases had lymphoid hyperplasia and were stained for adenovirus. We identified 2 positive cases, which also showed epithelial proliferation and viral inclusions. One involved a 6-year-old male and the other involved a 5-year-old female, without intussusception. Adenovirus can infect the appendix and clinically mimic acute appendicitis without intussusception. We recommend that all negative appendices be evaluated for lymphoid hyperplasia and epithelial viral changes and possibly be stained with immunoperoxidase staining if indicated. We speculate that adenovirus may play a role in the pathogenesis of acute appendicitis.

Discovery of human immunodeficiency virus infection by immunohistochemistry on lymph node biopsies from patients with unexplained follicular hyperplasia.

Over the last 10 years, 240 cases of hyperplasic lymphadenitis have been systematically tested in our institution for the presence of the human immunodeficiency virus (HIV). This series comprised patients between 15 and 90 years (median of age: 38.51) without a past history of HIV infection. The technical approach consisted in an immunohistochemical procedure with a monoclonal antibody against the p24-gag protein of HIV. Among the 240 cases, 105 had a true follicular hyperplasia. Overall, this survey found that 4 cases (3 males and 1 female) were positive for p24-gag without previous knowledge of HIV infection (4/240=1.66%). HIV infection was further confirmed by serologic and molecular investigations in all cases. These results were seen exclusively in those cases with prominent follicular hyperplasia (4/105=3.80%). Staining with the anti-p24 antibody was intense and restricted to the follicular dendritic cell networks. In one case, beside hyperplasic germinal centers, one could see a regressed onion bulblike structure. One important conclusion can be drawn from this study. A systematic research of HIV proteins should be performed in all lymph node biopsies with marked follicular hyperplasia, in a context of polyadenopathy, fever, and general status alteration. Besides giving an accurate diagnosis, this approach may be helpful in cases of recent infection in which anti-p24 antibodies are not yet detectable in the serum.

Lymphoproliferative disorders in Costa Rica and simian virus 40.

BACKGROUND AND OBJECTIVES: Simian virus 40 (SV40) is an oncogenic DNA virus implicated in some human malignancies, including lymphomas. In the present masked case-control study, we investigated the prevalence of SV40 sequences and the expression of the viral oncoprotein, large tumor antigen (T-ag), in lymphomas and control specimens from patients negative for the human immunodeficiency virus in Costa Rica. DESIGN AND METHODS: Coded specimens were anlyzed by polymerase chain reaction for SV40 and Epstein-Barr virus (EBV). SV40 sequences were confirmed by Southern blot and DNA sequence analysis. Immunohistochemistry was used to detect the expression of SV40 T-ag in coded samples and to immunophenotype the lymphomas. RESULTS: When samples were decoded, SV40 DNA sequences were detected significantly more often in lymphomas than in control samples (30/125, 24% vs. 0/91, 0%; p=0.001). SV40 DNA was detected in 26% and 10% of non-Hodgkin's and Hodgkin's lymphomas, respectively. EBV DNA was detected in 10% of lymphomas and 33% of control specimens. None of the lymphomas was positive for both SV40 and EBV. Expression of SV40 T-ag was detected in 64% of B-cell lymphomas that contained T-ag DNA sequences and in none of the samples negative for viral DNA. Not all cells in a positive tumor expressed T-ag and the reactions were relatively low intensity. A germinal center B-cell-like profile was frequently associated with SV40-positive lymphomas. Of note, 20% of patients with SV40-related lymphomas were born in the 1970s and 1980s. INTERPRETATION AND CONCLUSIONS: These results indicate that SV40 is significantly associated with some B-cell neoplasms in Costa Rica today.