Kaposi sarcoma
- Lesion
Kaposi sarcoma is a vascular tumour driven by a herpesvirus (HHV-8). It produces purple skin spots and is most aggressive in untreated AIDS.
What it is
Kaposi sarcoma is an intermediate-grade vascular neoplasm caused by human herpesvirus 8 (KSHV) in people whose immune control of the virus fails. The virus infects endothelial and spindle cells and expresses genes that drive proliferation and block apoptosis (for example a viral cyclin D and a viral G-protein coupled receptor that induces VEGF). It occurs in four settings: classic (older men of Mediterranean or Eastern European ancestry), endemic African, transplant-associated (iatrogenic) and AIDS-associated (epidemic).
Structure
- Patch: irregular dilated vascular spaces in the dermis with lymphocytes, plasma cells and hemosiderin-laden macrophages.
- Plaque: dermal proliferation of jagged vascular channels lined by plump spindle cells, with extravasated red cells and hemosiderin.
- Nodule: sheets of plump spindle cells forming slit-like spaces filled with red cells; hyaline globules; more mitoses.
- Markers: CD31, CD34, ERG and nuclear HHV-8 LANA-1.
The four clinical forms of Kaposi sarcoma
| Form | Who | Course |
|---|---|---|
| Classic (European) | Older men of Mediterranean, Eastern European or Jewish ancestry | Slow; plaques on lower legs |
| Endemic (African) | HIV-negative children and young adults in sub-Saharan Africa | Can be aggressive, involving lymph nodes |
| Transplant-associated | Solid-organ transplant recipients on immunosuppression | Often regresses when immunosuppression is reduced |
| AIDS-associated (epidemic) | People with untreated HIV, especially men who have sex with men | Widespread; responds to antiretroviral therapy |
Clinical notes
- Visceral lesions can bleed in the gut or obstruct airways; most deaths in the AIDS form came from opportunistic infections rather than the tumour.
Test yourself
Think of the answer, then tap the question to see it.
Which virus causes Kaposi sarcoma?
Human herpesvirus 8 (Kaposi sarcoma-associated herpesvirus, KSHV).
What is the histology of nodular Kaposi sarcoma?
Sheets of plump spindle cells forming slit-like vascular spaces with extravasated red cells and hemosiderin.
How can transplant-associated Kaposi sarcoma regress?
By reducing immunosuppression, which restores immune control of HHV-8.
Elsewhere in DurgiPedia
Connections
Microorganisms1
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Kaposi Sarcoma Treatment (PDQ®)–Patient Version (National Cancer Institute, 2025).
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Representative model, for educational purposes only.