context: Kaposi's sarcoma ( KS) is a type of cancer. Tumors with tiny new blood vessels grow below the surface of the skin and in membranes of your mouth, nose, eyes, and anus. It can spread to your lungs, liver, stomach, intestines, and lymph nodes, which are glands that help you fight infection. Researchers have found that Kaposi's sarcoma is caused by a herpes virus, HHV-8, also called KSHV. It affects 8 times more men than women. It may spread through sexual contact, but we don't know for sure. KS was once rare, affecting older men from Eastern European or Mediterranean families, young African men, or people who had undergone organ transplants. Now HIV is the most common cause. Because people with HIV have weakened immune systems, they're more likely to develop certain cancers, including KS. Most severe cases happen when someone has AIDS, the late stage of HIV infection, but skin lesions can also show up earlier. They're a sign your immune system isn't at full strength. Skin lesions tend to get worse when you also have other infections. Treating the HIV virus with antiretroviral therapy ( ART) is the best way to treat KS, too, especially early on. Anti- HIV drugs have dropped the rate of KS cases by 80%-90% from the beginning of the AIDS epidemic in the early 1980s. The most visible signs of Kaposi's sarcoma are lesions on the skin: flat, painless spots that are red or purple on white skin and bluish, brownish, or black on dark skin. Unlike bruises, they don't turn white when you press on them. They aren't itchy, and they don't drain. They're not life-threatening. New spots may show up each week. For some people, these lesions change slowly. They may grow into raised bumps or grow together. When KS spreads elsewhere, it can be life-threatening. You may have: Trouble eating or swallowing Queasiness, vomiting, and belly pain from bleeding and blockages inside Severe swelling in your arms, legs, face, or scrotum Serious coughing or shortness of breath Your doctor may diagnose Kaposi's sarcoma simply by looking at your skin. To confirm it, he may take a sample of tissue from a spot and look at it under a microscope, which is called a biopsy. If you have trouble breathing, your doctor may use a thin tube with a light (a bronchoscope) to look into your breathing passages. Or, if you have tummy troubles, he may want to look inside your guts through a lighted tube during a procedure called an endoscopy. Your treatment will depend on how many lesions you have and how big they are and where they are, as well as how well your immune system is working. In many cases, ART is the best way to treat active Kaposi's sarcoma. It may even clear up the skin lesions. If you have just a few, you could have them removed. That won't cure you, but it can make your skin look better. Your doctor can cut the tissue out or freeze it to destroy it. Radiation can kill the cancer cells or keep them from growing. A machine can direct it toward the lesions on your body, or your doctor may put radioactive needles, seeds, or wires inside you near the cancer. Once KS has spread, you'll need meds that go throughout your whole body to kill the cancer. Chemotherapy drugs for Kaposi's sarcoma include: Doxorubicin ( Adriamycin, Doxil) Paclitaxel ( Taxol) Vinblastine ( Velban) Chemotherapy can have side effects, including hair loss, vomiting, and fatigue. If you're HIV-positive, you also need to consider that chemo can lower your platelet and white-blood-cell counts, and raise your chances of an infection. Another type of drug treatment, called biological therapy, works by boosting your immune system. Your doctor may prescribe interferon alfa ( Intron A) if your CD4 cell count is over 200 and you have a fairly healthy immune system. Targeted therapies, such as monoclonal antibody therapy and tyrosine kinase inhibitors ( TKIs), are being tested in clinical trials. These try to attack the cancer and keep it from growing without harming healthy cells.