Cases Of Kaposi's Sarcoma Research Articles

Kaposi's sarcoma-associated herpesvirus protein ORF75 among HIV-1 patients in Kenya.

BackgroundHistology is used to identify Kaposi’s sarcoma (KS) in countries with low resources to fund healthcare costs. Approximately 95% of KS cases can be detected using a polymerase chain reaction.ObjectiveTo determine the presence of the open reading frame 75 (ORF75) gene associated with Kaposi’s sarcoma herpes virus among HIV-1/AIDS patients and to describe morphological presentations of KS.MethodsThis was a retrospective, descriptive study of archived tissue blocks collected from 2013 to 2016. Haematoxylin and eosin staining was used to identify KS. Deoxyribonucleic acid from archived tissue blocks was extracted and a nested polymerase chain reaction was used to detect the ORF75 gene.ResultsAll 81 cases in this study had been diagnosed as HIV-1 positive, of which 68 had hallmark features of KS in the histology report and 13 had features suggestive of KS (‘KS-like’). Microscopic identification of KS by haematoxylin and eosin staining was considered a significant indicator of KS herpes virus ORF75 gene positivity (p = 0.002). The ORF75 gene was detected in 60.5% (49/81) of tissue blocks; 27.2% were men (22/81) and 33.3% were women (27/81). The ORF75 gene was observed to be present in up to 15.4% (2/13) of the cases reported to have KS-like features.ConclusionFollowing the initial diagnosis of KS by histology, the ORF75 gene was fur-ther detected from both cases that had hallmark features of KS as well as among cases with KS-like fea-tures.

A clinical case of Kaposi sarcoma in a patient with TB/HIV co-infection

The article describes a clinical case of Kaposi sarcoma in a patient with concurrent tuberculosis, HIV infection with severely compromised T-cell immunity, viral hepatitis B and C, and substances and alcohol abuse. Also, the patient had low adherence to treatment with anti-tuberculosis and antiretroviral drugs.

Kaposi sarcoma among people living with HIV in the French DAT'AIDS cohort between 2010 and 2015.

BackgroundAlthough antiretroviral therapy (ART) has reduced the risk of Kaposi sarcoma (KS), KS cases still occur in HIV‐infected people.ObjectiveTo describe all KS cases observed between 2010 and 2015 in a country with high ART coverage.MethodsRetrospective study using longitudinal data from 44 642 patients in the French Dat’AIDS multicenter cohort. Patients’ characteristics were described at KS diagnosis according to ART exposure and to HIV‐plasma viral load (HIV‐pVL) (≤50 or >50) copies/mL.ResultsAmong the 209 KS cases diagnosed during the study period, 33.2% occurred in ART naïve patients, 17.3% in ART‐experienced patients and 49.5% in patients on ART, of whom 23% for more than 6 months. Among these patients, 24 (11.5%) had HIV‐pVL ≤50 cp/mL, and 16 (66%) were treated with a boosted‐PI‐based regimen. The distribution of KS localization did not differ by ART status nor by year of diagnosis.LimitationsData on human herpesvirus 8, treatment modalities for KS and response rate were not collected.ConclusionHalf of KS cases observed in the study period occurred in patients not on ART, reflecting the persistence of late HIV diagnosis. Factors associated with KS in patients on ART with HIV‐pVL ≤50 cp/mL remain to be explored.

Immune reconstitution inflammatory syndrome and human immunodeficiency virus infection.

Kaposi sarcoma is a low grade multi-focal vascular tumour of endothelial origin. It is the commonest neoplasm in patient with HIV infection and is one of the AIDS-defining illness. In the era of effective highly active antiretroviral therapy (HAART), Kaposi sarcoma is less commonly seen in recent days. However, in some occasion, immune reconstitution inflammatory syndrome (IRIS) can occur after initiation of HAART. Here, we would like to illustrate a case of Kaposi sarcoma as a result of IRIS after initiation of HAART.

Kaposi sarcoma in people living with HIV: incidence and associated factors in a French cohort between 2010 and 2015.

Kaposi sarcoma is still observed among people living with HIV (PLHIV) including those on ART with undetectable HIV viral load (HIV-VL). We aimed to assess Kaposi sarcoma incidence and trends between 2010 and 2015 in France and to highlight associated factors. Retrospective study using longitudinal data from the Dat'AIDS cohort including 44 642 PLWH. For the incidence assessment, Kaposi sarcoma cases occurring within 30 days of cohort enrollment were excluded. Demographic, immunological, and therapeutic characteristics collected at time of Kaposi sarcoma diagnosis or at last visit for patients without Kaposi sarcoma. Among 180 216.4 person-years, Kaposi sarcoma incidence was 76 (95% CI 64.3-89.9)/10 person-years. Multivariate analysis (Poisson regression) revealed the positive association with male sex, MSM transmission route, lower CD4 T-cell count, higher CD8 T-cell count, not to be on ART, whereas HIV follow-up time, duration with an HIV-VL 50 copies/ml or less were negatively associated with Kaposi sarcoma. According to the different models tested, HIV-VL, CD4 : CD8 ratio and nadir CD4 cell count were associated with Kaposi sarcoma. Moreover, stratified analysis showed that patients with a CD4 : CD8 ratio 0.5 or less or a CD8 T-cell count greater than 1000 cells/μl were at higher risk of Kaposi sarcoma regardless of the CD4 T-cell count. This study showed that in a resource-rich country setting with high ART coverage, Kaposi sarcoma still occurred among PLWH. CD8 hyperlymphocytosis and CD4 : CD8 ratio should be now considered as two useful markers to better identify patients at increased Kaposi sarcoma risk, including those with a CD4 T-cell count greater than 500 cells/μl.

Residential proximity to an industrial incinerator and risk of soft-tissue sarcoma, 1999-2014.

exposure to dioxins has been associated with an increased risk of soft-tissue sarcoma (STS). In a study relating to 1989-1998, a significant excess of STS was found in the population living within a 2-kilometre radius of an industrial incinerator located inside a Mantua industrial site. In the years 1974-1991, the incinerator burned hazardous chlorine-containing waste that resulted in the emission of dioxins. After 1991, it was exclusively fed with organic synthetic products not containing chlorine. the aim of this case-control study was to estimate the STS risk, for 1999-2014, in the population living in four Mantua districts located in the proximity of the industrial incinerator, compared to subjects resident in the remaining parts of Mantua province, regarded as non-exposed. the cases analysed were subjects with a first-incident diagnosis of STS between 1999 and 2014 resident at diagnosis in Mantua Province. Cases were selected using the 2013 criteria from the WHO classification. Cases of Kaposi sarcoma, PEComas and STS occurring in a previously irradiated field were excluded. For each case of soft-tissue sarcoma, four controls were randomly selected from all individuals resident in Mantua Province included in the Regional Health Service database in the years of incidence of each case (calendar year), and individually matched for gender and year of birth. Residential and occupational history (for employment in an oil refinery, and petrochemical and chemical plants) was reconstructed for all study subjects (cases and controls) since 1961. Subjects were considered exposed if they had lived in the four Mantua districts most affected by the incinerator emissions, on the basis of an atmospheric dispersion model and a dioxins biomonitoring survey. Four analyses were performed according to variously defined residential time windows. Odds ratios and corresponding 95% confidence intervals (95%CI) were calculated using conditional regression models adjusted for occupational history. 391 cases (203 males and 188 females) and 1,564 controls were included. The number of exposed cases and controls in the four analyses were 8 and 55, 8 and 60, 15 and 68, and 15 and 73, respectively. An increased STS risk was not observed in any of the analyses. in this study, no increased risk of STS was observed in subjects who had lived, in the study's time window, in the Mantua districts most affected by the incinerator emissions. The most likely interpretation of the present finding is a real STS risk reduction for subjects resident in the most recent decades in the Mantua districts most affected by the incinerator emissions, due to the cessation of burning chlorine-containing waste in the incinerator, development of some remediation plans, and implementation of new industrial procedures.

Human herpesvirus-8 latent nuclear antigen-1 expression in kaposi's sarcoma cases as seen in Nnewi, Anambra State: (A 10-year retrospective study)

Background: Human herpesvirus-8 (HHV-8) is a recognized major causative agent of Kaposi sarcoma (KS). Latent nuclear antigen-1 (LNA-1) is constitutively expressed in all HHV-8-infected cells. The index study emphasizes the role of immunohistochemistry in the diagnosis of KS in Nnewi, Anambra State, Nigeria. After thorough searches in Google Scholar and PubMed, we discovered that our study is the first to employ HHV-8 LNA-1 immunohistochemistry in the diagnosis of KS in Nigeria and other parts of Africa. Materials and Methods: It is a 10-year retrospective analysis of all histopathologically diagnosed KS cases from the archives of both Nnamdi Azikiwe University Teaching Hospital and Pathocon Specialist Clinic and Research Institute Nnewi. Pathology report forms of all KS cases and their blocks were retrieved and recut, and the recut slides were reviewed to confirm the cases. Of the 69 cases of KS retrieved, only 58 that met the inclusion criteria were analyzed using HHV-8 LNA-1 immunohistochemical stains. Results: Of these 58 cases, 20.7' were KS mimickers misdiagnosed as KS while 79.3' were true KS. Confirmed or HHV-8 LNA-1-positive KS cases accounted for 1.3' of all solid malignancies and 15.7' of all sarcomas, with majority presenting as cutaneous lesions mainly involving the lower limb (52.2') and predominantly (69.6') in nodular stage. Conclusion: HHV-8 LNA-1 is an important immunohistochemical marker in confirming diagnosis of KS.

AIDS-associated Kaposi sarcoma mimicking bleeding peptic ulcer disease

Kaposi sarcoma (KS) was the first AIDS defining malignancy described, and it commonly involves the skin, although visceral lesions exist. Visceral KS lesions are easy to miss, especially when symptoms are atypical or suggestive of another condition. This is a case of KS of the stomach in an HIV/AIDS patient presenting with symptoms, suggestive of bleeding peptic ulcer disease.

ORAL KAPOSI SARCOMA: A CASE REPORT

Kaposi sarcoma (KS) is an uncommon angioproliferative endothelial neoplasm. The pathogenesis of KS is likely multifactorial, but the infection of the cells with the human herpesvirus 8 (HHV-8) and HIV infection represents a consistent etiologic factor. We report a case of KS associated with HIV infection. A 34-year-old male patient showed an asymptomatic nodular lesion on the anterior vestibular gingiva of the maxilla with purple color and slow evolution. The diagnostic hypothesis was of pyogenic granuloma. Excisional biopsy was performed, and results revealed the presence of fascicles of spindle cells and slit-like vascular spaces, which frequently contained erythrocytes. The immunohistochemical analysis showed positivity for the viral antigens of HHV-8. Thus, the histopathologic diagnosis of KS was established. After the final diagnosis, laboratory tests were performed, which revealed HIV infection. The patient died after 3 months of severe immunosuppression and pneumonia.

Atypical presentation of classic Kaposi sarcoma in circumcised penis presenting as an ulcerative nodule with human herpesvirus 8 (HHV8) positivity and successfully treated with only local excision

IntroductionAlthough the Kaposi sarcoma (KS) is one of the AIDS defining entity and seen in almost one third of HIV infected patients with low CD4 cell counts, it is not uncommon in HIV seronegative persons, but genital KS is rare, particularly in people without risk factors for HIV infection. Isolated penile KS is an unusual manifestation, especially as solitary nodule with ulceration, in HIV seronegative patient.Case presentationWe report such a case of Kaposi sarcoma showing HHV-8 positivity in an elderly male Arabian patient with a delay in prompt diagnosis, but treated successfully with 3 3 years follow-up after limited local surgical excision.ConclusionThe general practitioners, venereologists and urologists should think of KS as a possibility in such lesion and consider early biopsy.

Intravascular Colonization of Kaposi Sarcoma: Expanding the Spectrum of Specific Infiltrates of B-Cell Chronic Lymphocytic Leukemia

B-cell chronic lymphocytic leukemia (CLL), a low-grade malignancy consisting of CD5(+), CD23(+), and CD43(+) small B lymphocytes, is the most frequent leukemia in the western world. Patients with CLL may exhibit skin changes characterized by histopathologic evidence of infiltration by atypical B lymphocytes, also known as "specific cutaneous infiltrates of CLL"; in addition, CLL is known to be associated with an increased risk of second cancers, including Kaposi sarcoma (KS). The combination of KS and CLL within the same cutaneous biopsy specimen has only rarely been described. We report a peculiar case of KS occurring in a patient with CLL, in which histopathological evaluation of KS lesions revealed prominent accumulation of CLL lymphocytes within neoplastic vascular spaces. We believe that our findings represent a novel example of intravascular colonization of vascular neoplasms by neoplastic lymphoid cells, further expanding the evergrowing spectrum of specific cutaneous infiltrates of CLL.

Impact of Antiretroviral Therapy on the Risk of Recurrence in HIV-1 Infected Patients with Kaposi Sarcoma: A Multicenter Cohort Experience.

Kaposi sarcoma (KS) remains a relevant malignancy in human immunodeficiency virus (HIV)-infected patients with a non-standardized management; despite past suggestions that ritonavir-boosted protease inhibitor (bPI)-based regimens could be preferable, no combination antiretroviral therapy (cART) regimen was demonstrated to outperform the others and the impact of new drugs, drug classes or paradigms was never investigated nor proven better than previous therapeutic regimes. In order to do this, we retrospectively collected data regarding HIV-infected patients with a diagnosis of KS last seen in six Italian centers after 1 January 2013. A total of 104 KS cases in 99 patients was analyzed for 945.34 patient-year follow-up (PYFU). Twenty-six patients had visceral localizations. Thirty-three patients were treated with chemotherapy, four with electrochemotherapy, and 12 with α-interferon (α-IFN). At censor, 22% received a bPI-based, 14% a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based, and 28% an integrase inhibitor (INI)-based standard cART, 24% a less drug regimen and 12% a mega-cART. Twelve recurrence episodes were observed in seven patients for an incidence of 1.27 per 100 PYFU. Two patients with no evidence of recurrence episodes died for other reasons. In our experience, KS recurrence episodes were infrequent. Despite the increasing use of new antiretroviral drug classes and new treatment paradigms, no excess of recurrence episodes was observed in patients receiving such cART regimens.

1266. Cancer among HIV-Positive Patients in Cali, Colombia: A Retrospective Hospital-Based Study

BackgroundCancer has been a significant feature of the HIV epidemic from the beginning, being the most frequent Kaposi sarcoma (KS) and hematolymphoid malignancies. However, the behavior of these two diseases is limited in our context. The study aimed to determine the trends of cancer among HIV/AIDS patients between 2011 and 2016.MethodsA retrospective hospital-based study was conducted at Fundación Valle del Lili, Cali, Colombia. The study included HIV-positive patients diagnosed with cancer after infection. HIV registry was cross-linked with a population-based cancer registry to obtain IARC/WHO ICD-O-3 classification and follow-up information on all patients. A descriptive analysis of the variables was performed. Survival analysis was carried out using the Kaplan–Meier method. Differences between cancer survival were assessed through the log-rank test.ResultsFrom 2,051 HIV-positive patient’s records between 2011 and 2016, 95 patients were diagnosed with cancer after HIV infection. The median age was 43 years (IQR=33–57), and 88% were male. Types of cancer were: Kaposi’s sarcoma 17%, hematolymphoid malignancies 21% and other cancer 62%. The probability of cancer diagnosis after HIV diagnosis was 36.26% (CI 95% [26.53–46.05]) at one-year follow-up for all malignancies. Overall survival of the patients was 77.41% (CI 95% [64.76–86]) at 5 years follow-up, since HIV diagnostic. Hematolymphoid malignancies and KS survival were 50% (CI 95% [20.85–73.61]) and 65.63% (CI 95% [35.80–84.14]) at 5 years follow-up, respectively. There was a statistically significant difference between KS, hematolymphoid and other cancer cases survival (P = 0.0178).ConclusionThis study showed the role of HIV in cancer survival for KS and hematolymphoid malignancies mainly, in a developing country. It is necessary to join efforts in our context to reduce HIV cases and associated malignancies.Disclosures All authors: No reported disclosures.

328. Kaposi Sarcoma in High Population ART Utilization Setting: An Observational Study in Botswana

BackgroundDespite population antiretroviral treatment (ART) utilization exceeding UNAIDS 90-90-90 targets, Kaposi sarcoma (KS) remains one of the most prevalent malignancies in Botswana. We sought to examine the characteristics and outcomes of KS in the context of high ART utilization.MethodsConsenting patients at one of four oncology centers for KS treatment were enrolled prospectively (October 2010 to March 2019) and followed quarterly for 5 years. Survival was estimated using Kaplan–Meier estimator and predictors assessed with Cox proportional hazards modeling.ResultsA total of 408 KS patients were enrolled and of those, 396 (97%) were HIV-positive and included in analyses. Median age at diagnosis was 40 years (IQR: 34.1, 46.7) and 247 patients (62%) were male. The median CD4 cell count at the time of KS diagnosis was 253 cells/mL (IQR: 134, 364) and 279 (73%) were receiving ART at the time of KS diagnosis. Among those on ART, the median duration of ART prior to KS diagnosis was 11.9 months (IQR: 2.7, 46.7). The proportion receiving ART prior to KS increased during the surveillance period from 58% to 80% (P < 0.001). Of the 248 (62.6%) patients with recent measurement, 91% had HIV-1 RNA < 1000 copies/mL. Five-year overall survival was 73% (95% CI 68–78%). In multivariable analysis, Female sex and higher income were associated with improved survival, but not age or CD4 cell count. The duration of ART was significantly associated with survival (P = 0.02), with improved survival for individuals on ART < 6 months compared with longer ART (HR 0.54; 95% CI 0.29–0.98). The incidence of KS cases declined by nearly 50%, but has remained relatively stable since 2015.ConclusionSurvival rates in this cohort were comparable to other KS cohorts. While KS treatment initially declined with ART expansion, KS remains a significant disease burden in Botswana with 80% of cases occurring among individuals receiving ART. Disclosures All authors: No reported disclosures.

1932 The Answer Is on Your Skin: A Case of GI Bleeding Secondary to Kaposi Sarcoma

INTRODUCTION: GI tract bleeding in AIDS patients carries with it a significant degree of morbidity, with a unique differential including different opportunistic infections and malignancies. Kaposi Sarcoma (KS) is a form of malignancy associated with the human herpes-virus 8, recognized as an AIDS defining illness, and is typically recognized by violaceous cutaneous lesions. KS can also have widespread involvement of the visceral organs including the GI tract, where it can manifest as anything from GI bleeding to diarrhea, abdominal pain, nausea/vomiting and weight loss. Here, we describe a case of AIDS-related KS leading to profound GI bleeding. CASE DESCRIPTION/METHODS: A 29 year old male with a history of AIDS (CD4 of 44 cells/mm3and viral load of 18,000 copies/mL) in the setting of anti-retroviral therapy (ART) non-compliance presented with subacute onset shortness of breath, palpitations and malaise over the prior week. Upon review of systems, he endorsed diarrhea and melena over the same timeframe, while denying any other GI tract symptoms. Vital signs on presentation were significant for tachycardia to 103 bpm. Physical exam was notable for violaceous small lesions in buccal mucosa, hard palate, arms and back. His initial labs indicated severe anemia with a hemoglobin level of 4.9 g/dL with a ferritin level of less than 10 indicating severe iron deficiency anemia. After initial resuscitation, the patient underwent upper and lower endoscopy. His EGD showed multiple small round, heaped up ulcers in the gastric antrum, body, and fundus, along with similar ulcers in the second part of the duodenum. His colonoscopy showed similar lesions found in the transverse colon and rectum as illustrated in the images below. Biopsies taken from those lesions along with skin punch biopsies confirmed the diagnosis of Kaposi Sarcoma. He was discharged on Emtricitabine/Tenofovir and Darunavir/Cobicistat with follow up after several months showing dramatic improvement in his skin lesions and resolution of his gastrointestinal symptoms. DISCUSSION: The endoscopic appearance of KS in the GI tract is unique, often appearing as hemorrhagic nodules or plaques, however still requires tissue biopsy for diagnosis. Treatment is centered on ART with the use of systemic chemotherapy typically only needed in case of severe symptoms or lack of response to ART. Our case is a testament to the broad differential to be considered in HIV/AIDS patients with GI bleeding, of which Kaposi Sarcoma should be considered.

Incidence and outcome of Kaposi sarcoma after hematopoietic stem cell transplantation: a retrospective analysis and a review of the literature, on behalf of infectious diseases working party of EBMT.

The incidence, the clinical characteristics, and the outcome of Kaposi sarcoma (KS) in patients after hematopoietic stem cell transplantation (HSCT) were assessed. During the period 1987-2018, 13 cases of KS were diagnosed, 3 females and 10 males, median age of 50 years, median time from HSCT of 7 months. KS had an incidence of 0.17% in allogeneic and 0.05% in autologous HSCT. HHV-8 was documented in eight of nine tumor tissue samples assessed. The organ involvement was: skin in nine, lymph nodes in six, oral cavity in four, and visceral in three patients, respectively; seven patients had >1 organ involved. Five patients had immunosuppression withdrawn, whereas four and three patients received radiotherapy and chemotherapy, respectively. Eight patients are alive (median follow-up 48 months, range 5-128), whereas five patients died after a median time of 8 months from the diagnosis of KS. However, no death was caused by KS. We conclude that the incidence of KS after HSCT is very low. Although KS can be managed with the reduction of immunosuppression, visceral forms may require chemotherapy and/or radiotherapy. The low prevalence of KS indicates that screening for HHV-8 serology and surveillance for HHV-8 viremia are not indicated in HSCT patients.

Common Cutaneous Neoplasms in Patients with Immunodeficiency: A Case Series

Abstract Through humoral and cell-mediated mechanisms, the immune system plays a vital role in protecting every organ system. Disorders of the immune system may result in various cutaneous manifestations, including cutaneous malignancies. In patients with immunodeficiency, the risk of development of malignant cutaneous neoplasms is substantially increased. This increased risk may be due to oncogenic viruses that find a suitable microenvironment for tumorigenesis and cancer development. A subset of cutaneous malignancies that develop in patients with immunodeficiency may show aggressive clinical and biological behavior. Here, we report six cases of highly aggressive and deadly cutaneous neoplasms that arose in patients with a known history of immunodeficiency: two cases of Kaposi sarcoma in patients with immunosuppression due to human immunodeficiency virus infection; a case of Merkel cell carcinoma and a case of squamous cell carcinoma (SCC) in patients receiving immunosuppressive drugs after organ transplant; a case of multiple cutaneous tumors, including invasive melanoma, SCC, and sebaceous carcinoma, in a patient with hypogammaglobulinemia and a history of organ transplant; and a case of basal cell carcinoma and melanoma in situ in a patient with primary immunodeficiency.

Visceral Kaposi Sarcoma Presenting as Small Bowel Intussusception: A Rare Presentation and Call to Action

Surgical emergencies related to visceral involvement of Kaposi sarcoma (KS) are rare complications of the disease. In this report, we describe a case of visceral KS causing small bowel intussusception in a young, previously undiagnosed human immunodeficiency virus (HIV)-positive patient. Southern surgeons should be particularly attentive to HIV/AIDS-related disease as a cause of surgical pathology, particularly in the southeast, and can play a significant advocacy role for improved access to HIV/AIDS diagnostic and treatment services.

Kaposi sarcoma in Southern Finland (2006-2018).

Kaposi sarcoma (KS) age-standardized incidence rate is below 0.3 per 100,000 in Nordic countries. Data on KS in Finland have been sparse. A retrospective review of all the patients with KS cases managed in the Helsinki University Central Hospital between 2006 and 2018. Forty patients (median age at diagnosis 45years, 38 males) were included. About 2.5 new cases were diagnosed per year (incidence 0.16 /100,000). The different subtypes of KS were: human immunodeficiency virus (HIV) (65%), classical KS (30%), and immunodepression (5%). Patients with HIV were significantly younger, more likely to have cutaneous lesions of the face, the trunk, and mucosal lesions,and KS withinlymph nodes and inner organs. KS was diagnosed at the same time as HIV in 77% of cases, 28% with CD4-cell level above 300cells/mm3 . Among the patients with classical KS (n=12), 75% were of Finnish origin, 41% had a second primary malignancy diagnosed, and 25% had noninsulin dependent diabetes mellitus. Among HIV patients, 27% had another AIDS-related illness, 7% of the patients developed lymphoproliferative disorders, and 7% a hemophagocytic syndrome. Patients with HIV were always treated with antiviral therapy, with pegylated liposomal doxorubicin in 57% of the cases. Local radiotherapy was the main treatment for other KS types. None of the 5 deaths during follow-up was related to KS. Classical KS (KS-CLA) occurs among native Finns, frequently with other present malignancies. Screening of HIV and other malignancies is warranted in new cases of KS.

Kaposi sarcoma.

Kaposi sarcoma (KS) gained public attention as an AIDS-defining malignancy; itsappearance on the skin was a highly stigmatizing sign of HIV infection during the height of the AIDS epidemic. The widespread introduction of effective antiretrovirals to control HIV by restoring immunocompetence reduced the prevalence of AIDS-related KS, although KS does occur in individuals with well-controlled HIV infection. KS also presents in individuals without HIV infection in older men (classic KS), in sub-Saharan Africa (endemic KS) and in transplant recipients (iatrogenic KS). The aetiologic agent of KS is KS herpesvirus (KSHV; also known as human herpesvirus-8), and viral proteins can induce KS-associated cellular changes that enable the virus to evade the host immune system and allow the infected cell to survive and proliferate despite viral infection. Currently, most cases of KS occur in sub-Saharan Africa, where KSHV infection is prevalent owing to transmission by saliva in childhood compounded by the ongoing AIDS epidemic. Treatment for early AIDS-related KS in previously untreated patients should start with the control of HIV with antiretrovirals, which frequently results in KS regression. In advanced-stage KS, chemotherapy with pegylated liposomal doxorubicin or paclitaxel is the most common treatment, although it is seldom curative. In sub-Saharan Africa, KS continues to have a poor prognosis. Newer treatments for KS based on the mechanisms of its pathogenesis are being explored.