History and exam

Key diagnostic factors

common

presence of risk factors

Recognition of the clinical category of the patient (classic [sporadic]; endemic [observed in sub-Saharan Africa]; epidemic [AIDS-related]; iatrogenic [transplant-related]) is key to the correct diagnosis, with knowledge of the patient's HIV status, ethnicity (African, Mediterranean, or Jewish) and history of iatrogenic immunosuppression, particularly transplantation.

age >50 years

Can affect patients of all ages. Classic KS usually occurs in people over the age of 50 years, with substantial risk increase after the age of 70 years.[16][29]

male sex

All epidemiological forms of KS have a predilection for males. In 2022, the age-standardised incidence rates of KS were estimated to be 0.6 cases per 100,000 population in men and 0.3 cases per 100,000 in women.[10]

geographical location: central Africa or the Mediterranean

Occurs worldwide. Prior to the AIDS epidemic, incidence rates for endemic KS were greater for the Democratic Republic of Congo, Uganda, Tanzania, and Cameroon (>6 per 1000 person-years) than for southern or north Africa (≤2 per 1000 person-years).[21]

Classic (sporadic) KS has the highest incidence rates in Mediterranean countries.[4]

HIV infection

People with HIV are approximately 500 times more likely to be diagnosed with KS than the general population.[11][12]

HIV-associated KS usually arises in people with low CD4+ T-cell counts and high HIV viral load. Effective antiretroviral therapy (ART) reduces the risk of developing KS.

KS may sometimes occur in people with well-controlled HIV, most often in older patients.[2]

human herpesvirus-8 (HHV-8, also known as Kaposi's sarcoma-associated herpesvirus [KSHV]) infection

Existing HHV-8 infection is necessary for the development of KS.

Individuals with HHV-8-related diseases, such as multicentric Castleman's disease and primary effusion lymphoma (PEL), are at risk for developing concomitant KS.[26]

immunosuppression

Iatrogenic KS may be observed in patients receiving immunosuppressive therapy, particularly organ transplant recipients.[3]

In the US, the incidence of KS among transplant recipients is reported to be between 8.8 and 12.4 per 100,000 recipients.[19][20] The incidence of iatrogenic (transplant-related) KS varies with different ethnic and geographical regions.[17][18][19]

skin lesion

Lesions are multifocal, asymmetrically distributed, and non-pruritic. They vary in size (ranging from several millimetres to centimetres in diameter) and colour (pink, red, purple, brown, or blue). Cutaneous lesions may be difficult to distinguish in dark-skinned people. They can be papular, nodular, plaque-like, bullous-like, or fungating with skin ulceration and secondary infection.[3] Long-standing lesions may become indurated (woody) and hyperkeratotic.[Figure caption and citation for the preceding image starts]: Multiple pink-purple Kaposi's sarcoma nodules on the lower extremityFrom the collection of Dr Bruce J. Dezube; used with permission [Citation ends].com.bmj.content.model.Caption@56e4e80b[Figure caption and citation for the preceding image starts]: Kaposi's sarcoma cutaneous purple-brown plaque on the footFrom the collection of Dr Bruce J. Dezube; used with permission [Citation ends].com.bmj.content.model.Caption@4951b049

oral lesion

Oral KS frequently affects the hard palate, gingiva, and dorsum of the tongue.

Approximately 23% of patients with HIV-associated KS may present with oral lesions; global prevalence of oral lesions in patients with HIV with KS has been estimated to be 5%.[44][45]​​​​

Oral lesions can present as macules, papules, nodules, and exophytic masses of varying size and colour. Advanced lesions may become ulcerated from masticatory trauma and secondary infection.

lymphadenopathy

Involvement of the lymph nodes by KS may be generalised and result in small, hard lymph nodes or massive lymphadenopathy.

lymphoedema

May be painful in the legs, genitalia, and face, out of proportion to the extent of disease, and can mask underlying KS.

Other diagnostic factors

uncommon

weight loss

May occur from gastrointestinal tract involvement or the underlying condition (e.g., HIV infection).

abdominal pain

KS of the gastrointestinal tract can cause non-specific abdominal pain.

gastrointestinal (GI) bleeding

KS of the GI tract can cause upper or lower GI tract bleeding.

diarrhoea

KS of the gastrointestinal tract can infrequently cause diarrhoea.

dyspnoea

Pulmonary KS can present with shortness of breath.

haemoptysis

KS-related bleeding of the lower respiratory tract can result in haemoptysis.

chest pain

Pulmonary KS can present with non-specific chest pain.

fever

KS of any organ may be accompanied by pyrexia.

Risk factors

strong

male sex

All epidemiological forms of KS have a predilection for males.

In 2022, the age-standardised incidence rates of KS were estimated to be 0.6 cases per 100,000 population in men and 0.3 cases per 100,000 in women.[10]​​

HIV infection

People with HIV are approximately 500 times more likely to be diagnosed with KS than the general population.[11][12]​

immunosuppressive therapy

Iatrogenic KS may be observed in patients receiving immunosuppressive therapy, particularly organ transplant recipients.[3]

In the US, the incidence of KS among transplant recipients is reported to be between 8.8 and 12.4 per 100,000 recipients.[19][20]​​ The incidence of iatrogenic (transplant-related) KS varies with different ethnic and geographical regions.[17][18][19]

human herpesvirus-8 (HHV-8, also known as Kaposi's sarcoma-associated herpesvirus [KSHV]) infection

Existing human herpesvirus-8 (HHV-8) infection is necessary for the development of KS.

Individuals with HHV-8-related diseases, such as multicentric Castleman's disease and primary effusion lymphoma (PEL), are at risk for developing concomitant KS.[26]

central African ethnicity

Prior to the AIDS epidemic, incidence rates for endemic KS were greater for the Democratic Republic of Congo, Uganda, Tanzania, and Cameroon (>6 per 1000 person-years) than for southern or north Africa (≤2 per 1000 person-years).[21]

weak

drug abuse

Among people with HIV, those with intravenous drug use, non-injection drug use, and alcohol use disorder are more likely to have KS.[27]

A subsequent study found no association between use of recreational drugs (amphetamines, amyl nitrate [poppers], cocaine, cannabis) and risk for KS in HIV- and human herpesvirus-8 (HHV-8)-coinfected men who have sex with men.[28]

Jewish ethnicity

Older men of Jewish descent are at risk of developing KS.[16]

Mediterranean ethnicity

Classic (sporadic) KS has the highest incidence rates in Mediterranean countries.[4]

Prior to the AIDS era, the incidence of KS in Italy was up to 10 times higher than in other western countries.[15]

age <5 years or >50 years

Individuals of all ages can present with KS. However, in African children the highest incidence occurs in those less than 5 years of age. Classic KS usually occurs in people over the age of 50 years, with substantial increase in risk after the age of 70 years.[16][29]

men who have sex with men

Risk of KS appears to be higher in men who have sex with men, regardless of HIV status and ethnic origin.[30][31]​​​[32]

Black American ethnicity

KS is more common in black Americans than white Americans (age-adjusted incidence rate 1.19 vs. 0.49 per 100,000, respectively; 2008-2012 data). Black Americans are more likely to be diagnosed at a younger age and experience higher mortality rates.[6][7]

Data from 1998 to 2012 indicate decreasing incidence of KS in the white American population; however, increasing incidence is seen in the black American population from the mid-2000s.[7]

Certain sub-populations have been identified with significant increases (e.g., young, non-Hispanic black men in southern US regions).[8]

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