Kaposi's sarcoma: absence of cytomegalovirus antigens

Cutaneous vascular proliferations. Part III. Malignant neoplasms, other cutaneous neoplasms with significant vascular component, and disorders erroneously considered as vascular neoplasms

In this third and last part of our review of cutaneous vascular proliferations we include malignant vascular neoplasms and a group of heterogeneous cutaneous neoplasms characterized by a significant vascular component. We also review some disorders that, in our opinion, have been erroneously considered as vascular neoplasms. We review the epidemiologic, histogenetic, clinical, and histopathologic aspects of Kaposi's sarcoma in its four distinctive variants (classic, African-endemic, immunosuppressive drug-associated, and AIDS-associated Kaposi's sarcoma). There is still controversy about whether Kaposi's sarcoma represents a reactive vascular proliferation or a true neoplastic proliferation. In any event, most authors believe that Kaposi's sarcoma does not produce metastatic disease, but rather develops in multifocal fashion. However, Kaposi's sarcoma may cause death, especially in immunosuppressed patients. Epithelioid hemangioendothelioma, Dabska's tumor, and retiform hemangioendothelioma are examples of low-grade angiosarcoma. In contrast, cutaneous angiosarcomas, including the clinical variants of angiosarcoma of face and scalp in elderly patients, angiosarcoma associated with lymphedema, and radiation-induced angiosarcoma are highly aggressive neoplasms with poor prognosis and most patients die within a short period after presentation. A group of benign and relatively frequent cutaneous neoplasms, including multinucleate cell angiohistiocytoma, angiofibroma, angioleiomyoma, angiolipoma, cutaneous angiolipoleiomyoma, and cutaneous angiomyxoma are here covered because of their significant vascular component. Finally, we review briefly a series of cutaneous disorders that have been erroneously considered as vascular neoplasms. Kimura's disease is an inflammatory reactive condition of unknown origin, "benign" angioendotheliomatosis is a reactive intravascular proliferation of endothelial cells that occurs in the skin as a response to a variety of stimuli, "malignant" angioendotheliomatosis is an intravascular lymphoma, and acral pseudolymphomatous angiokeratoma of children (APACHE) is better interpreted as a pseudolymphoma.

Kaposi's sarcoma. Epidemiology, pathogenesis, histology, clinical spectrum, staging criteria and therapy

The acquired immunodeficiency syndrome (AIDS) epidemic has had a profound impact on our understanding of Kaposi's sarcoma (KS). Epidemiologic features suggest a sexually transmitted cofactor in the pathogenesis of AIDS-associated KS (AIDS-KS), and several putative agents have received intense scrutiny. Cell culture studies suggest that the angiogenesis of AIDS-KS is stimulated by both human immunodeficiency virus proteins and growth factors that may be involved in the development and progression of AIDS-KS, thereby providing a rationale for new therapeutic interventions. The dermatologist is uniquely qualified to provide care for the majority of patients with KS, as many patients have cutaneous lesions amendable to local therapy (cryotherapy, intralesional therapy, simple excision). Patients requiring more aggressive local therapy (radiation therapy) or systemic therapies (interferon, chemotherapy) can be easily recognized. Standardized staging criteria provide assistance for determining appropriate local or systemic therapy and for evaluating and comparing responses to new therapies. This article reviews the epidemiology, pathogenesis, histologic features, clinical spectrum, staging criteria, and treatment of KS.

Kaposi's sarcoma: a review of gene expression and ultrastructure of KS spindle cells in vivo

The ultrastructural features and the gene expression pattern of Kaposi's sarcoma (KS) spindle cells in vivo suggest that KS is a tumor of the mixed cell type. The expression pattern of cytokines and cytokine receptors in the tumor lesion, together with the results obtained from in vitro characterization of KS-derived cells, provide evidence that paracrine mechanisms of growth factor action are important for the maintenance of KS. The reports on virus infection of KS cells suggest an indirect role of virus infection in the induction of KS, most likely mediated by immunostimulation and subsequent production of cytokines.

Human immunodeficiency virus (HIV) transcripts identified in HIV-related psoriasis and Kaposi's sarcoma lesions

Persons with HIV infection sometimes develop aggressive psoriasis or Kaposi's sarcoma (KS) not usually seen in other immunosuppressed patients. However, a specific and direct pathophysiological role for HIV-1 in these AIDS-associated disorders remains unclear since HIV has not been easily detected in these skin lesions. By combining in situ hybridization with the sensitive detection technique of confocal laser scanning microscopy, we have demonstrated HIV RNA transcripts in 5 of 15 lesional skin biopsies from HIV-infected psoriasis patients, and in 3 of 8 Kaposi's sarcoma biopsies from HIV-infected patients. HIV transcripts were not detected in normal appearing skin from HIV-infected patients or in psoriatic and normal skin biopsies from uninfected individuals (P = 0.006). Although previous attempts to demonstrate viral sequences in psoriasis and KS lesions have been unsuccessful, in situ hybridization with confocal microscopy has shown the presence of HIV RNA transcripts predominantly within CD4+, Factor XIIIa positive dermal dendrocytes. HIV or cytokines produced by infected cells in skin lesions may therefore play a direct role in the pathogenesis of HIV-associated psoriasis and KS.

HIV infection of human gastrointestinal submucosal cells: an in vitro model that mimics Kaposi's sarcoma

Infection of human gastrointestinal submucosal mesenchymal cells with HIV-1 led to cell populations with abnormal growth properties, increased synthesis of endothelial cell and angioblast markers, and release of angiogenic factors. This system may be the first in vitro model for HIV-induced Kaposi's sarcoma.

Analysis of human KS biopsies and cloned cell lines for cytomegalovirus, HIV-1, and other selected DNA virus sequences

Investigation into a possible role of several human viruses, including human cytomegalovirus (HCMV), human immunodeficiency virus (HIV-1), hepatitis B virus (HBV), human herpesvirus 6 (HHV6), and Epstein-Barr virus (EBV) in the pathogenesis of Kaposi's sarcoma (KS) has resulted in the lack of an association of these viruses in KS biopsy and cloned KS cell line specimens. Since nearly all patients with KS, including those with HIV-associated KS, have a high incidence of HCMV infection, HCMV has been proposed to be etiologically associated with KS. Moreover, our previous studies showed the retention of HCMV morphological transforming region II (mtrII) in both transformed and tumor-derived cell lines. As a result, we focused on the nucleic acid hybridization analysis of both KS biopsies from AIDS patients as well as cloned KS endothelial cell lines for HCMV mtrII sequences. We also analyzed KS biopsy and KS cloned cell line specimens for HIV-1, HBV, HHV6, and EBV sequences, since these viruses have also been implicated in the etiology of KS. In one set of experiments, Southern blot analysis revealed the presence of HCMV mtrII sequences in two of six KS biopsies; in other experiments, HBV sequences were found in one of seven KS biopsies. No hybridization in any biopsy tissue was detected for HIV-1 DNA sequences. The analysis of six independently derived cloned KS cell lines was next studied. All these lines were negative for hybridization to the HCMV mtrII transforming fragment as well as to subgenomic fragments of HHV6 and EBV.(ABSTRACT TRUNCATED AT 250 WORDS)

Kaposi's sarcoma cells: long-term culture with growth factor from retrovirus-infected CD4+ T cells

Studies of the biology and pathogenesis of Kaposi's sarcoma (KS) have been hampered by the inability to maintain long-term cultures of KS cells in vitro. In this study AIDS-KS-derived cells with characteristic spindle-like morphology were cultured with a growth factor (or factors) released by CD4+ T lymphocytes infected with human T-lymphotropic virus type I or II (HTLV-I or HTLV-II) or with human immunodeficiency virus type 1 or 2 (HIV-1 or HIV-2). Medium conditioned by HTLV-II-infected, transformed lines of T cells (HTLV-II CM) contained large amounts of this growth activity and also supported the temporary growth of normal vascular endothelial cells, but not fibroblasts. Interleukin-1 and tumor necrosis factor-alpha stimulated the growth of the KS-derived cells, but the growth was only transient and these could be distinguished from that in HTLV-II CM. Other known endothelial cell growth promoting factors, such as acidic and basic fibroblast growth factors and epidermal growth factor, did not support the long-term growth of the AIDS-KS cells. The factor released by CD4+ T cells infected with human retroviruses should prove useful in studies of the pathogenesis of KS.

Angiogenic properties of Kaposi's sarcoma-derived cells after long-term culture in vitro

Cells derived from lung biopsies and pleural effusions from AIDS patients with Kaposi's sarcoma (KS) of the lungs were established in long-term culture with the aid of conditioned medium from HTLV-II-transformed T cells (HTLV-II CM). These AIDS-KS cells were similar to the so-called spindle cells in KS lesions and had some of their features. They produced factors that supported their own growth (autocrine) and the growth of other cells (paracrine), including umbilical vein endothelium and fibroblasts. That the AIDS-KS cells also expressed potent angiogenic activity was demonstrated by the chorioallantoic membrane assay and by subcutaneous inoculation of AIDS-KS cells into nude mice, which resulted in the development of angiogenic lesions composed of mouse cells and showing histological features similar to those of human KS lesions. These data suggest that AIDS-associated KS and possibly other types of KS may be initiated by signals that induce the growth of particular cells (spindle cells of lymphatic or vascular origin) and the expression of autocrine and paracrine activities.

Spontaneous healing of Kaposi's angiosarcoma of the penis

We report a case of Kaposi's angiosarcoma of the penis. Few cases have been reported of the initial and exclusive involvement of Kaposi's angiosarcoma of the glans penis and prepuce. Our case is unique because of the number of lesions and the spontaneous remission.

Detection of cytomegalovirus DNA in classic and epidemic Kaposi's sarcoma by in situ hybridization

Several lines of evidence have suggested an etiologic association of cytomegalovirus (CMV) with Kaposi's sarcoma. This contention is supported by a pathoepidemiologic survey of 54 cases of acquired immunodeficiency syndrome (AIDS) at our own institution. Of the 27 patients with documented Kaposi's sarcoma, 24 (89%) showed histologic evidence of CMV infection (cytomegalic cells with viral inclusions), whereas only 9 (33%) of the patients with AIDS without Kaposi's sarcoma showed hallmarks of CMV infection. In an attempt to address this question further, we have searched for the presence of CMV nucleic acid sequences in a series of 25 patients with AIDS and Kaposi's sarcoma, using the technique of in situ DNA hybridization. The reliability of the in situ technique is demonstrated, and the technique is shown to be more sensitive than the detection of viral inclusions within Kaposi's sarcoma lesions by routine light microscopy. However, only 20% of our cases showed evidence of CMV involvement, and the CMV-positive cells within the affected Kaposi's sarcoma lesions were few and sparsely distributed. In addition, a companion series of 6 elderly patients with "classic" Kaposi's sarcoma showed no evidence of CMV infection by either conventional microscopy or in situ hybridization. These results do not support the notion of a strong association between Kaposi's sarcoma and CMV, unless the CMV sequences are present at a copy number too low for detection by these methods. The implications of these findings in light of current theories of CMV oncogenesis are discussed.

Kaposi's sarcoma: immunoperoxidase staining for cytomegalovirus

An immunoperoxidase technique was used to test for cytomegalovirus (CMV) proteins in lesions of Kaposi's sarcoma from 19 patients with acquired immune deficiency syndrome (AIDS) and 3 patients without AIDS. CMV proteins could not be detected in any of the cases of Kaposi's sarcoma. Thus, while CMV genetic material may be present in these cells, the virus is not actively directing the synthesis of proteins. This eliminates reactivation of latent CMV in tumor tissue, or late infection of Kaposi's sarcoma cells as explanations for the elevated antibody titers to CMV and other evidence of CMV infection in patients with Kaposi's sarcoma. However, the possibility remains that exposure to CMV occurs as a primary event in the development of Kaposi's sarcoma. These findings indicate that, as in Kaposi's sarcoma of the elderly, the virus is inactive in Kaposi's sarcoma cells of patients with AIDS, and there is no difference between the two lesions in immunoperoxidase staining for CMV proteins.