Absence of human herpesvirus 8 DNA sequences in vascular tumors of the liver

Primäre Sarkome und Sarkommetastasen in der Leber

The considerable progress made in radiology, in surgical management with curative intent, and in the identification of molecularly targeted small molecules, such as the tyrosine kinase inhibitor imatinib mesylate, in the treatment of gastrointestinal stromal tumors has greatly influenced the treatment of sarcoma manifestations within the liver. This requires not only the unequivocal pathomorphological differentiation of sarcomas from other tumor entities, e. g. spindle cell dedifferentiated/pleomorphic carcinomas, aggressive non-Hodgkin lymphomas or amelanotic malignant melanomas, but also an accurate subtyping of this complex group of tumors. Additionally to macroscopic and histological findings, the recognition of characteristic immunophenotypic constellations and, at least in some types of sarcoma, the identification of molecular signatures, have greatly expanded the diagnostic tools in pathology.

Demonstration of human herpesvirus 8 in a case of primary vaginal epithelioid angiosarcoma by in situ hybridization, electron microscopy, and polymerase chain reaction

We demonstrate the presence of human herpesvirsus 8 (HHV-8) in a primary vaginal location of angiosarcoma (AS) by polymerase chain reaction (PCR), in situ hybridization, and ultrastructural direct visualization of viral particles. The latter two techniques for the first time confirm HHV-8 detection in an AS by PCR; these results contribute to the debate caused by the controversial data produced by the almost exclusive use of PCR for investigating the possible presence of HHV-8 in AS, and its possible implications. Moreover, the investigated AS is the seventh published primary vaginal one, and the fourth unrelated to radiotherapy. Interestingly, the affected patient had used a ring pessary for 10 years because of an uterovaginal prolapse.

Spectrum of Kaposi's sarcoma-associated herpesvirus, or human herpesvirus 8, diseases

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), discovered in 1994, is a human rhadinovirus (gamma-2 herpesvirus). Unlike other human herpesviruses (herpes simplex virus, Epstein-Barr virus, varicella-zoster virus, cytomegalovirus, HHV-6, and HHV-7), it is not widespread in the general population and has many unique proteins. HHV-8 is strongly associated with all subtypes of Kaposi's sarcoma (KS), multicentric Castleman's disease, and a rare form of B-cell lymphoma, primary effusion lymphoma. In addition, HHV-8 DNA sequences have been found in association with other diseases, but the role of the virus in these diseases is largely unconfirmed and remains controversial. The seroprevalence of HHV-8, based on detection of latent and lytic proteins, is 2 to 5% in healthy donors except in certain geographic areas where the virus is endemic, 80 to 95% in classic KS patients, and 40 to 50% in HIV-1 patients without KS. This virus can be transmitted both sexually and through body fluids (e.g., saliva and blood). HHV-8 is a transforming virus, as evidenced by its presence in human malignancies, by the in vitro transforming properties of several of its viral genes, and by its ability to transform some primary cells in culture. It is not, however, sufficient for transformation, and other cofactors such as immunosuppressive cytokines are involved in the development of HHV-8-associated malignancies. In this article, we review the biology, molecular virology, epidemiology, transmission, detection methods, pathogenesis, and antiviral therapy of this newly discovered human herpesvirus.

The emerging role of the human herpesvirus 8 (HHV8) in human neoplasia

The human herpesvirus 8 (HHV8) was initially described and characterised in Kaposi's sarcoma tissue. The virus was found in the lesion of most cases of Kaposi's sarcoma. Whilst there is a large body of evidence to implicate its role in the pathogenesis of Kaposi's sarcoma, it has recently been found that the virus may also be important in a number of other human neoplasias. This review will examine the molecular pathology of HHV8 in the pathogenesis of Kaposi's sarcoma and summarise the current evidence and postulated mechanisms in its role in other human neoplasias.

Mesenchymal tumors of the liver

Primary angiosarcoma of the liver accounts for up to 2% of all primary liver tumors and is the second most common primary malignant neoplasm of the liver. Approximately 10 to 20 new cases are diagnosed every year in the United States and the prevalence varies from 0.14 to 0.25 per million. In an autopsy series from Chicago, one hepatic angiosarcoma was noted for every 30 cases of hepatocellular carcinoma.

Expression of the caveolins in dermal vascular tumors

INTRODUCTION

Histopathologic criteria are usually sufficient for the accurate distinction of benign from malignant dermal vascular tumors. A minority of cases, however, pose a vexing diagnostic dilemma. Recent studies suggest that caveolin, a scaffolding cell membrane protein, may prove helpful in predicting the biologic behavior of endothelial-derived neoplasms.

METHODS

We analyzed a series of 30 dermal vascular tumors including 12 lobular capillary hemangiomas (LCH), 4 cases of targetoid hemosiderotic hemangiomas (TH), 4 cases of tufted angioma (TA), 12 cases of Kaposi's sarcoma (KS), 4 epithelioid (EH) and 1 spindle cell hemangioendothelioma (SH), and 4 cases of angiosarcoma (AS). The distribution of immunoreactivity was analyzed by quantifying cell membrane staining in each case.

RESULTS

There was a statistically significant difference in the expression of caveolin between LCH (mean labeling index=91.6), TH (mean labeling index=89.7), and TA (mean labeling index=87.2) and the cases of KS (mean labeling index=21.6, EH mean labeling index= 23.1), and the AS (mean labeling index=6.3).

CONCLUSIONS

These results indicate that antibodies to caveolin may be useful in separating benign and malignant dermal vascular tumors and possibly implicates this peptide in their pathogenesis.

Human herpesvirus type 8 in salivary gland tumors

BACKGROUND

The new human herpesvirus type 8 (HHV-8) has been detected in all types of Kaposi's sarcomas, as well as in body-cavity lymphomas and Castleman's disease, furthermore molecular biologic studies have identified a number of potential viral oncogenes. There is evidence for sexual transmission of HHV-8 in HIV-seropositive patients, but the route of infection among the HIV-seronegative population is uncertain. Findings of HHV-8 DNA in saliva in some cases are suggestive of nonsexual transmission associated with latent infection of the salivary gland (as it is known for EBV, CMV, HHV-6 and HHV-7).

OBJECTIVE

As little is known about the etiological factors of salivary gland tumors and to give more insights into HHV-8 cell tropism normal salivary gland tissue (n=12) and different salivary glands neoplasm (n=58) were tested for HHV-8 sequences and antigens in HIV-seronegative patients.

STUDY DESIGN

Biopsies of both normal salivary gland and tumors were investigated for HHV-8 sequences. A nested-PCR method was used for amplification of HHV-8 DNA fragments and the nature of the amplification products was confirmed by Southern blot hybridization. In addition, we used an in situ hybridization technique and immunohistochemical staining for detection of HHV-8 infected cells. The sera of the respective patients were tested for anti-HHV-8 antibodies using commercial IFA and an ELISA-assay.

RESULTS

HHV-8 DNA sequences could be detected in one bilateral MALT-lymphoma of the parotid gland of a HHV-8 seropositive female patient suffering from Sjögren's syndrome (SS). The remaining parotid samples did neither show HHV-8 sequences nor HHV-8 antigens. Using above assays only one additional patient was seropositive for HHV-8.

CONCLUSION

Our data suggest that HHV-8 does not usually infect the salivary gland in HIV-seronegative patients and does not seem to play a pathogenic role in vascular and epithelial salivary gland neoplasm. Pathogenic role of HHV-8 in Sjögren's syndrome associated MALT-lymphoma remains unclear and should be subject of further studies.

Kaposi sarcoma of major salivary gland origin: A clinicopathologic series of six cases

BACKGROUND

Kaposi sarcoma (KS), one of the defining tumors of acquired immune deficiency syndrome (AIDS), is rarely identified in the major salivary glands. To the authors' knowledge, no previous published series has evaluated the clinicopathologic aspects of this tumor in major salivary glands.

METHODS

Six cases of salivary gland KS, diagnosed between 1970 and 1998, were retrieved from the files of the Oral and Maxillofacial Pathology Registry of the Armed Forces Institute of Pathology. Histologic features were reviewed and special stains, immunohistochemical studies, and in situ hybridization were performed (n = 4). Patient follow-up data were obtained.

RESULTS

The patients included 6 men ages 20-73 years (average, 53.0 years). Patients presented clinically with a mass in the submandibular (n = 4) or parotid (n = 2) gland region. Symptoms were present for a mean of 13.7 months. The tumors measured 1-4 cm (average, 2.5 cm) in greatest dimension. Histologically, the tumors exhibited the usual features of KS: a spindle cell vascular proliferation arranged in fasciculated bundles, variable nuclear pleomorphism, mitotic figures, extravasated erythrocytes, and hyaline globules. Five patients were serologically positive for human immunodeficiency virus (HIV) (three homosexual males, one infected by a contaminated blood transfusion, and one with an unknown risk factor). Human herpesvirus-8 (HHV-8) was present in all cases tested (n = 4). Patients were treated with surgical excision (n = 6), followed by chemotherapy (n = 1) for the single patient with other foci of KS (rectal). Three patients died of AIDS-related infectious complications and one of congestive heart failure, whereas the remaining patients are alive with AIDS but free of salivary gland KS.

CONCLUSIONS

Salivary gland enlargement is frequently identified in HIV positive or AIDS patients. Although rare, it is important to consider KS in the differential diagnosis of other AIDS-related salivary gland manifestations (infections and tumors).

Epithelioid hemangioendothelioma, multiple focal nodular hyperplasias, and cavernous hemangiomas of the liver

Malignant vascular neoplasms of the liver are uncommon. We report the case of a young woman who developed an epithelioid hemangioendothelioma of the liver associated with multiple focal nodular hyperplasias and hepatic cavernous hemangiomas. Such an unusual association is probably not fortuitous and could support the theory that focal nodular hyperplasia is a reaction to an abnormal vascular supply rather than a true neoplasm.