Wolf in sheep's clothing: advanced Kaposi sarcoma mimicking vulvar abscess

Kaposi sarcoma is a vascular neoplastic disorder that is associated with the acquired immunodeficiency syndrome (AIDS). The causative factor in Kaposi sarcoma is human herpes virus-8. This complication of AIDS has a predilection for homosexual males and is rarely associated with the female AIDS population. However, we present a case of Kaposi sarcoma mimicking the benign and common Bartholin gland abscess. A search of the literature including the MEDLINE database revealed a single report of Kaposi sarcoma presenting as a vulvar mass, but not as a suspected Bartholin abscess. The history, presentations, risk factors, and treatments available for Kaposi sarcoma are also discussed in this report.     

Kaposi sarcoma secondary to pulmonary tuberculosis: a rare case

Kaposi sarcoma commonly occurs in HIV-positive and immunocompromised patients. We describe a case of Kaposi sarcoma that developed in an HIV-negative patient with tuberculosis. The Kaposi sarcoma completely regressed with antituberculous therapy without the institution of chemotherapy. The patient remained disease-free after a follow-up period of 20 months. Patients with Kaposi sarcoma should be monitored for coexisting diseases such as tuberculosis.     

Sarcoma

Sarcomas comprise a heterogeneous group of mesenchymal neoplasms. They can be grouped into 2 general categories, soft tissue sarcoma and primary bone sarcoma, which have different staging and treatment approaches. This review includes a discussion of both soft tissue sarcomas (malignant fibrous histiocytoma, liposarcoma, leiomyosarcoma, synovial sarcoma, dermatofibrosarcoma protuberans, angiosarcoma, Kaposi sarcoma, gastrointestinal stromal tumor, aggressive fibromatosis or desmoid tumor, rhabdomyosarcoma, and primary alveolar soft-part sarcoma) and primary bone sarcomas (osteosarcoma, Ewing sarcoma, giant cell tumor, and chondrosarcoma). The 3 most important prognostic variables are grade, size, and location of the primary tumor. The approach to a patient with a sarcoma begins with a biopsy that obtains adequate tissue for diagnosis without interfering with subsequent optimal definitive surgery. Subsequent treatment depends on the specific type of sarcoma. Because sarcomas are relatively uncommon yet comprise a wide variety of different entities, evaluation by oncology teams who have expertise in the field is recommended. Treatment and follow-up guidelines have been published by the National Comprehensive Cancer Network (www.nccn.org).     

Therapeutic options for human herpesvirus-8/Kaposi’s sarcoma-associated herpesvirus-related disorders

Human herpesvirus-8/Kaposi’s sarcoma-associated herpesvirus infection is associated with three proliferative disorders in immunocompromised patients – Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. These disorders often develop in patients with advanced AIDS who present a number of therapeutic challenges, underscoring the importance of continuing efforts dedicated to basic and clinical research in this field. In the era of highly active antiretroviral therapy, the incidence of AIDS and Kaposi’s sarcoma has considerably decreased, presumably due to enhanced anti-Kaposi’s sarcoma-associated herpesvirus immune responses, whereas the situation with primary effusion lymphoma and multicentric Castleman’s disease is more complex. Based on advances in the understanding of Kaposi’s sarcoma-associated herpesvirus-related disorders and availability of antiretroviral agents, current and future therapeutic approaches will be discussed.     

Kaposi sarcoma herpesvirus (KSHV) vFLIP oncoprotein induces B cell transdifferentiation and tumorigenesis in mice

Kaposi sarcoma herpesvirus (KSHV) is specifically associated with Kaposi sarcoma (KS) and 2 B cell lymphoproliferative diseases, namely primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). KS, PEL, and MCD are largely incurable and poorly understood diseases most common in HIV-infected individuals. Here, we have revealed the role of viral FLICE-inhibitory protein (vFLIP) in the initiation of PEL and MCD by specifically expressing vFLIP at different stages of B cell differentiation in vivo. Mice showed MCD-like abnormalities and immunological defects including lack of germinal centers (GCs), impaired Ig class switching, and affinity maturation. In addition, they showed increased numbers of cells expressing cytoplasmic IgM-λ, a thus far enigmatic feature of the KSHV-infected cells in MCD. B cell-derived tumors arose at high incidence and displayed Ig gene rearrangement with downregulated expression of B cell-associated antigens, which are features of PEL. Interestingly, these tumors exhibited characteristics of transdifferentiation and acquired expression of histiocytic/dendritic cell markers. These results define immunological functions for vFLIP in vivo and reveal what we believe to be a novel viral-mediated tumorigenic mechanism involving B cell reprogramming. Additionally, the robust recapitulation of KSHV-associated diseases in mice provides a model to test inhibitors of vFLIP as potential anticancer agents.     

New viruses shake old paradigms

Kaposi sarcoma–associated herpesvirus (KSHV) can establish latent infection in host cells. The latently infected cells can survive and proliferate with a few viral genes expressed. However, in some Kaposi sarcoma cells, KSHV undergoes a productive life cycle and causes cell lysis. A new study (see the related article beginning on page 124) demonstrates that, after KSHV infection or introduction of viral plasmids into host cells, viral DNA is rapidly lost. Lytic virus production with ensuing infections could balance the loss of the viral plasmids to maintain the virus in cancer cells.     

Computed tomography of rectal and perirectal disease in AIDS patients

Twenty-eight homosexual men with Kaposi sarcoma as part of the acquired immune deficiency syndrome (AIDS-related KS) and 2 homosexual men without AIDS were examined with abdominal and pelvic computed tomography (CT). Abnormalities of the rectum and perirectal areas were seen in 8 of the 30 patients on CT examination. Endoscopy and biopsy of the colon in these 8 cases revealed inflammatory changes in 6 patients and KS in 2. The CT abnormalities were not specific for inflammatory disease or tumor, and endoscopy with biopsy was necessary to establish an accurate diagnosis.     

Lymphoma of the appendix

A rare case of appendiceal lymphoma in a patient who presented with lower gastrointestinal bleeding is reported. The findings on double-contrast barium enema, computed tomography (CT), and ultrasound are described and the clinical features of the few previously reported cases of appendiceal lymphoma are discussed.     

Sarcoma-associated sarcoid reaction: Report of cutaneous sarcoid reaction in a patient with liposarcoma

Sarcoidosis is a systemic inflammatory condition in which noncaseating epithelioid cell granulomas appear within one or several body sites. Sarcoid reaction(also referred to as sarcoidal or sarcoid-like reaction) occurs in patients who do not fulfill the diagnostic criteria for systemic sarcoidosis but present with similar clinical and histological features. As sarcoma-associated sarcoid reactions are rare, we describe the features of sarcoid reaction that developed in a man with liposarcoma and summarize reports of other oncology patients with sarcoma-associated sarcoid reactions. A 68-yearold man with retroperitoneal liposarcoma presented for evaluation of erythematous dermal plaques on his left leg. Microscopic examination of a tissue specimen revealed multiple epithelioid granulomas in the superficial and mid-reticular dermis. Correlation of the clinical presentation and histopathologic findings established a diagnosis of liposarcoma-associated cutaneous sarcoid reaction. Sarcoid reactions have been described in only seven individuals with sarcoma, including two patients with leiomyosarcoma and one patient with either carcinosarcoma, Kaposi sarcoma, liposarcoma, malignant peripheral nerve sheath tumor, rhabdosarcoma, or synovial sarcoma. Sarcoidal granulomas most commonly develop within the locoregional draining lymph nodes. Sarcoid reactions may also affect other organs, such as the lungs, skin, and spleen.     

Kaposi sarcoma and paracoccidioidomycosis in the same fragment of oral mucosa biopsy: a rare association in human immunodeficiency virus-positive patient. A case report

The immunossuppression caused by HIV infection makes the affected individuals more susceptible to some diseases including infections, neoplasms, or even the association between them. Kaposi sarcoma (KS) is the most common AIDS-related neoplasm, featured as an angioproliferative disorder. Its cause seems to be related to the human herpesvirus type 8 and it is usually associated with lower CD4+ T cell count. Oral involvement is frequent, presenting red to blue-purplish plaques, maculaes, and nodules. On the other hand, paracoccidioidomycosis (PCM) is a systemic mycosis, endemic in Latin America, caused by Paracoccidioides brasiliensis. This mycosis is not commonly related to human immunodeficiency virus (HIV) infection, although PCM can be present in immunosuppression cases. Oral lesions, as granulomatous ulcers, are often identified in seropositive patients with PCM. A rare case, in which a male HIV-positive patient presented simultaneously Kaposi sarcoma and PCM in the same fragment of oral mucosa biopsy, is described. To the best of our knowledge, this concomitant association had not been previously described.     

Recurrent Kaposi sarcoma of the ear in an HIV‐negative patient: A case report with review of the literature. Is ear a predilection site for Kaposi sarcoma in HIV‐negatives?

While Kaposi sarcoma (KS) of the head and neck is common in HIV‐positives, it is a rare presentation in HIV‐negatives. It is important to consider KS in the differential diagnosis of ear lesions in HIV‐negative patients.     

Virology,pathogenetic mechanisms,and associated diseases of Kaposi sarcoma-associated herpesvirus (human herpesvirus 8)

Kaposi sarcoma-associated herpesvirus (KSHV) is a recently discovered and characterized member of the herpesvirus family. It is one of a few viruses proved to be associated with tumorigenesis in humans. Its causal association with 4 clinical and epidemiologic variants of Kaposi sarcoma (classic, endemic, iatrogenic, and acquired immunodeficiency virus-associated) as well as with several lymphoproliferative disorders (notably primary effusion lymphoma and multicentric Castleman disease) is reviewed critically. Issues related to the epidemiology, transmission, and molecular and serologic diagnosis are discussed. Several intriguing oncogenic mechanisms of KSHV infection have been identified. These are often dependent on the interaction of KSHV with other viruses, such as human immunodeficiency virus, Epstein-Barr virus, or both. However, important problems remain and once resolved will substantially enhance our understanding of oncogenesis in general and viral-induced oncogenesis in particular. This may also translate into improved treatment and perhaps prevention of this common and intriguing viral infection.     

Mucocele of the appendix: an important clinical rarity

Mucocele is an uncommon pathology of the vermiform appendix that can be confused with acute appendicitis. We present a case of an appendiceal mucocele associated with subacute, intermittent right lower quadrant discomfort. The diagnosis of appendiceal mucocele is an important one in that it can be associated with malignancies and other serious gastrointestinal, ovarian, and urological complications.     

CT Findings of retroperitoneal malignant mesenchymoma

Malignant mesenchymoma (MM) is a rare mesenchymal neoplasm which, by definition, demonstrates at least two distinct types of malignant mesenchymal differentiation. We present the computed tomographic (CT) findings of a 42-year-old female with a pathologically proven retroperitoneal MM consisting of osteoid production combined with foci of liposarcoma and Kaposi sarcoma. MM should be considered along with extraosseous osteosarcoma and teratoma in the differential diagnosis for unusual large heterogeneous retroperitoneal masses with massive calcification.     

The human herpesvirus 8 chemokine receptor vGPCR triggers autonomous proliferation of endothelial cells

We have used a novel conditional transgenic system to study the mechanisms of angioproliferation induced by viral G protein-coupled receptor (vGPCR), the constitutively active chemokine receptor encoded by human herpesvirus 8 (HHV8, also known as Kaposi sarcoma herpesvirus). Using this system, we were able to control temporal expression of vGPCR and to monitor its expression in situ via the use of the surrogate marker LacZ. Upon treatment with doxycycline (DOX), cells expressing vGPCR and LacZ (vGPCR/LacZ(+) cells) progressively accumulated in areas where angioproliferation was observed. Sorted vGPCR/LacZ(+) cells from angiogenic lesions expressed markers characteristic of endothelial progenitor cells, produced angiogenic factors, and proliferated in vitro. Prolonged treatment of transgenic mice with DOX led to development of tumors in the skin of ears, tail, nose, and paws. vGPCR/LacZ(+) cells were frequent in early lesions but scarce within these tumors. Finally, transfer of vGPCR/LacZ(+) cells into Rag1(-/-) mice treated with DOX led to angioproliferation and, with time, to development of tumors containing both vGPCR/LacZ(+) and vGPCR/LacZ(-) cells. Taken together, these results indicate that vGPCR triggers angioproliferation directly and suggest a novel role for this molecule in the pathogenesis of Kaposi sarcoma.     

Cytomegalovirus: nucleocapsid assembly and core structure.

New ultrastructual aspects of cytomegalovirus nucleocapsid assembly are illustrated in cells from a Kaposi sarcoma. The occurrence of viral deoxyribonucleoproteins in the form of strands and penetration of these strands into open capsids is illustrated. The geometrical arrangement of the core material of the nucleocapsid is aslo emphasized.     

Colesional cutaneous talaromycosis (penicilliosis) and Kaposi sarcoma in an HIV‐infected patient

HIV‐infected patients are at high risk of multiple pathologies. Accurate identification of multiple colesional pathologies is critical for the patient management. We report a distinctive case of colesional cutaneous talaromycosis and Kaposi sarcoma. Prudent histopathological examination and judicious use of adjunct diagnostic test are essential for the diagnosis.     

Acute appendicitis caused by acute myeloid leukemia

A case of appendiceal involvement by acute myeloid leukemia (AML) in an adult with recent history of AML transformed from myelodysplastic syndrome (MDS) was presented. Being aware of this rare presentation in particular in a patient with history of MDS and/or AML is important for prompt clinical diagnosis and management.