AIDS-associated Kaposi sarcoma
The outbreak of KS among young, previously healthy men who have sex with men (MSM) heralded the recognition of AIDS in 1981. AIDS-associated KS is the most common neoplasm in human immunodeficiency virus (HIV)-seropositive patients and is an AIDS-defining illness. This form of KS is primarily seen in the MSM population, but it can be seen in female partners of men with the disease in addition to HIV-infected women. About 40% of men with AIDS develop KS. Lesions may worsen during immune reconstitution inflammatory syndrome and may also appear in patients with HIV who have received long-term antiretroviral therapy (ART).
Patients with AIDS-associated KS often have multifocal cutaneous disease. Around 20% of patients will have concomitant visceral involvement, which places these patients at risk for hemorrhage from gastrointestinal (GI) lesions, cardiac tamponade, and pulmonary obstruction. Additionally, AIDS-associated KS is more likely than classic KS to display a rapidly progressive course.
Spindle cells of endothelial origin are the predominant cells affected. In the latent phase, HHV-8 antigens promote cell proliferation by inactivating the RB gene, which leads to transcription of S-phase genes and blocks apoptosis via p53 and p27Kip1 suppression. In the lytic phase, when tumor formation is noted, thousands of virion particles are assembled, resulting in cell lysis. HHV-8 requires additional cofactors for the development of KS. HIV coinfection acts as a stimulant for HHV-8 viral lytic expression and via its suppression of the immune system.
The introduction of ART dramatically decreased the incidence, morbidity, and mortality of AIDS-associated KS.
For discussion of classic, endemic, and iatrogenic forms of KS, see non-AIDS Kaposi sarcoma.
C46.0 – Kaposi's sarcoma of skin
420524008 – Kaposi's sarcoma associated with AIDS
Differential Diagnosis & Pitfalls
- Bacillary angiomatosis
- Lobular capillary hemangioma (pyogenic granuloma)
- Dermatofibrosarcoma protuberans
- Lichen simplex chronicus
- Prurigo nodularis
- Metastatic carcinoma or melanoma
- Pigmented basal cell carcinoma
- Blue rubber bleb nevus syndrome
- Tufted angioma
- Cavernous hemangioma
- Arteriovenous malformation
- Leukemia cutis
- Early KS may resemble a large junctional nevus, a port-wine stain, or an ecchymosis.
- Acroangiodermatitis of Mali
- Stewart-Bluefarb syndrome
- Hypertrophic lichen planus
- Erythema elevatum diutinum
- Angioinvasive fungal disease such as aspergillosis