Kaposi's sarcoma

Kaposi's sarcoma (KS) was first described in 1872 by the Hungarian dermatologist Moritz Kaposi. Before the AIDS epidemic it was a rare condition.

There are four different forms of KS:

  • Classic KS causes multiple skin lesions on the lower limbs. It is mainly seen in elderly men in Mediterranean or eastern European regions.
  • Endemic KS is found in children and young men in equatorial Africa. It is more virulent than the classic form.
  • Acquired KS occurs in people treated with immunosuppressive drugs, especially those who have received organ transplants. It goes away when the drugs are stopped.
  • Epidemic KS is the form associated with HIV infection. It tends to follow a more variable but potentially more aggressive course than other forms of KS.

KS most commonly presents as skin lesions which often appear when the immune system is still relatively intact. As long as it is confined to the skin, KS is not fatal and it is unlikely to be serious. However, for historical reasons, KS is diagnostic of AIDS. While it is most commonly found on the skin, KS can occur anywhere in the body.

Within the context of HIV and AIDS, KS predominantly affects gay men with HIV. For every five men infected with both HIV and human herpes virus 8 (HHV-8), the virus that causes KS, two will develop KS within ten years. KS has always been rare among HIV-positive drug users and people with haemophilia.1 A small number of gay men in the United States have KS but do not have HIV infection or AIDS. KS is rare among women, possibly due to hormonal factors, but is still more common in HIV-positive than HIV-negative women.1 2 If a woman with HIV develops KS, she is likely to have contracted HIV through unsafe sex with a bisexual man. KS may be more aggressive when it does occur in women.

KS used to be the most commonly diagnosed HIV-related malignancy. With the development of better treatments for KS, and the use of antiretroviral therapy, the incidence of KS declined significantly in the 1990s in western countries. KS remains a common opportunistic malignancy in people who have relatively advanced immunosuppression, but it is rarely a cause of death. Nevertheless, KS is associated with an elevated risk of death and there is some evidence that it can accelerate HIV disease.

References

  1. Atkinson JO et al. The incidence of Kaposi sarcoma among injection drug users with AIDS in the United States. J Acquir Immune Defic Syndr 37: 1282-1287, 2004
  2. Hessol NA et al. Cancer risk among participants in the Women's Interagency HIV Study. J Acquir Immune Defic Syndr 36: 978-985, 2004