K

Kaposi’s sarcoma A CANCERthat develops in the
connective tissues that support the SKIN, with
characteristic lesions on the skin and mucous
membranes. There are several types of Kaposi’s
sarcoma. The two that are most common in the
United States are AIDS-related Kaposi’s sarcoma
and transplant-related Kaposi’s sarcoma.
In 1994 researchers discovered that human
herpesvirus 8 (HHV-8), sometimes called Kaposi’s
sarcoma–associated herpesvirus (KSHV), causes
Kaposi’s sarcoma. However, the path of transmis-
sion remains uncertain. Like other herpesvirus
strains, HHV-8 can remain dormant in the body
for years without manifesting symptoms. A
healthy IMMUNE SYSTEMseems to hold HHV-8 in
check, preventing it from causing disease. Pro-
longed compromise of immune function, through
conditions such as HIV/AIDSor through IMMUNOSUP-
PRESSIVE THERAPYsuch as occurs following ORGAN
TRANSPLANTATION, allows HHV-8 to replicate (repro-
duce itself by taking over healthy cells) and cause
Kaposi’s sarcoma.
AIDS-related Kaposi’s sarcoma Nearly all
Kaposi’s sarcoma in the United States occurs in
people, predominantly men, who have AIDS.
Doctors consider the appearance of Kaposi’s sar-
coma a defining sign that INFECTION with HIV
(human immunodeficiency virus) has progressed
to the disease state of AIDS. The activation of both
HIV and HHV-8 may occur simultaneously, when
both are present. Advances in treatment options
for HIV/AIDS, notably highly active antiretroviral
therapy (HAART), delay the progression of HIV to
AIDS and consequently the appearance of Kaposi’s
sarcoma. About 6 percent of men with HIV/AIDS
who receive HAART develop Kaposi’s sarcoma,
compared to 20 percent among those who do not.

Transplant-related Kaposi’s sarcoma People

who undergo organ transplantation typically

receive immunosuppressive therapy, to prevent

organ rejection, for the rest of their lives. The

development of Kaposi’s sarcoma arises from the

immunosuppression, not the organ transplantation.

The American Cancer Society estimates that about

1 in 200 transplant recipients taking immunosup-

pressive therapy to prevent organ rejection

develop Kaposi’s sarcoma. People who take long-

term immunosuppressive therapy for other health

conditions are also at risk for Kaposi’s sarcoma.

Symptoms and Diagnostic Path

The key symptom of Kaposi’s sarcoma is the pres-

ence of its characteristic lesions, which are nodu-

lar and raised, in people with long-term

immunosuppression or who are HIV-positive. The

lesions start as small, raised areas and are most

common on the face, lower legs and feet, and gen-

itals, though can develop anywhere on the body.

They are usually darkly pigmented, often brown-

ish red or purple, and sometimes itch. As they

grow, the lesions may block the flow of blood or

lymph, causing painful swelling. Lesions some-

times develop within the connective tissues of

internal organs such as the LUNGS, where they can

cause difficulty BREATHING, or the intestines, where

they can cause GASTROINTESTINAL BLEEDINGand ILEUS

(intestinal obstruction).

The doctor can usually make a definitive diag-

nosis of Kaposi’s sarcoma on the basis of visible

lesions and immune or HIV status, with biopsy of

a representative lesion to confirm the diagnosis if

necessary. A chest X-ray can determine the pres-

ence of lesions in the LUNGS. Other imaging studies

such as COMPUTED TOMOGRAPHY (CT) SCAN and

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