Kaposi's Sarcoma

What Is It?

Kaposi's sarcoma is a type of cancer that is caused by a virus called human herpes virus 8. The tumors of Kaposi's sarcoma appear as red or purple patches on the skin, mouth, lungs, liver or gastrointestinal tract. It was considered a rare and relatively benign tumor from the year 1872, when it was first described, until the onset of the AIDS epidemic. The more aggressive form of the disease, which occurs in patients with severely weakened immune systems, is called AIDS-related Kaposi's sarcoma to distinguish it from the other, more benign forms. With the explosion of HIV/AIDS cases, this form of Kaposi's sarcoma has become far more common than the other types.

The four types of Kaposi's sarcoma are:

• Classic Kaposi's sarcoma — A rare, slow-growing skin tumor, usually affecting males of Italian or Eastern European Jewish ancestry.
• African Kaposi's sarcoma — Though extremely rare in the rest of the world, Kaposi's sarcoma occurs more frequently among young males in certain countries in equatorial Africa. Usually it is a slow growing tumor, but in some cases, the skin tumors can be aggressive, invading bone and tissue under the skin.
• Immunosuppressive treatment-related Kaposi's sarcoma — Patients who are taking immunosuppressive therapy for organ transplantation may develop this form of Kaposi's sarcoma. It sometimes improves if the immunosuppressive medication is reduced or changed.
• AIDS-related Kaposi's sarcoma — An opportunistic infection affecting people with late-stage HIV/AIDS. It usually appears as a rapidly progressing tumor affecting the skin, lymph nodes, gastrointestinal tract, lungs, liver and spleen. In the United States, 95 percent of the cases involve homosexual or bisexual men. The incidence of this tumor is decreasing with the advent of highly active retroviral therapy for HIV/AIDS.

Symptoms

The first symptoms of Kaposi's sarcoma are usually red, purple or brown patches, plaques, or nodules on the skin, often with a bruise-like appearance. In the classic, African and immunosuppressive forms of Kaposi's sarcoma, these lesions usually are slow-growing, progressing over years. As the disease gets worse, the lower legs may swell and, in some cases, the disease may spread to other organs.

In the AIDS-related form, however, the tumor is much more aggressive, often growing to cover larger areas, and forming tumorlike masses. At first, these lesions are typically soft and spongy, but over time, they usually become hard and solid. The surface of the tumor may form open ulcers, which may become infected. The disease rarely is confined to the skin, and often affects the mouth, lymph nodes, lungs, liver, spleen and gastrointestinal tract. When the tumor involves the lungs, it often causes cough, shortness of breath and wheezing. In the lungs, the disease often progresses rapidly, and may result in death from respiratory failure. However, when the disease involves the gastrointestinal tract, it rarely causes symptoms unless the disease is very advanced. In that case, patients may develop symptoms of intestinal obstruction (nausea, vomiting and abdominal pain) or bloody stools. If the lymph nodes become involved, severe swelling can occur, usually of the legs or face.