[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Blood vessels](https://durgical.com/en/general-pathology/areas/vessels/) › Kaposi sarcoma

# 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.

Updated Nov 12, 2026

## Key points

- Cause: HHV-8 infection plus immune deficiency; the virus is also linked to primary effusion lymphoma and multicentric Castleman disease.
- Classic form: indolent purple plaques on the lower legs of older men.
- AIDS-associated form: an AIDS-defining tumour; widespread skin, mouth, lymph node, gut and lung lesions; regresses with antiretroviral therapy.
- Transplant form: may regress when immunosuppression is reduced.
- Lesion evolves from patch to plaque to nodule.
- Immunohistochemistry: LANA-1 (HHV-8 latent nuclear antigen) is positive in tumour nuclei.

## 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.

## Memory aid

Herpes 8 plus a weak defence makes purple spindles: patch, plaque, then nodule, faster the weaker the defence.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/kaposi-sarcoma/)

[More Pathology questions →](https://durgical.com/en/practice/?f=pathology)

## Elsewhere in DurgiPedia

- [Secondary immunodeficiency: HIV, malnutrition, drugs, asplenia](https://durgical.com/en/immunology/secondary-immunodeficiency-hiv-malnutrition-drugs-asplenia/)

## Connections

## Related 4

- [Oncogenic viruses and H. pylori: the table to know](https://durgical.com/en/general-pathology/oncogenic-viruses-and-h-pylori-the-table-to-know/)
- [Benign vascular tumours](https://durgical.com/en/general-pathology/benign-vascular-tumours/)
- [Haemangioendothelioma and angiosarcoma](https://durgical.com/en/general-pathology/haemangioendothelioma-and-angiosarcoma/)
- [Tumour angiogenesis](https://durgical.com/en/general-pathology/tumour-angiogenesis/)

## Related conditions 2

- [Kaposi sarcoma](https://durgical.com/en/conditions/kaposi-sarcoma/)
- [HIV infection and AIDS](https://durgical.com/en/conditions/hiv-infection-and-aids/)

## Microorganisms 1

- [Human herpesvirus 8](https://durgical.com/en/microbiology/human-herpesvirus-8/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

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](https://www.cancer.gov/types/soft-tissue-sarcoma/patient/kaposi-treatment-pdq) (National Cancer Institute, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/general-pathology/kaposi-sarcoma/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/kaposi-sarcoma/