Kaposi Sarcoma

Kaposi sarcoma (KS) is a cancer that develops from the cells that line lymph or blood vessels. It usually appears as tumors on the skin or on mucosal surfaces such as inside the mouth. But these tumors can also develop in other parts of the body, such as in the lymph nodes (bean-sized collections of immune cells throughout the body), the lungs or digestive tract. 

With new treatments for HIV and AIDS, KS has become less common in the United States, and it now occurs at a rate of about 6 cases per million people each year. It’s still seen most often in people infected with HIV.

Types & Stages

There are four different types of Kaposi sarcoma defined by the different populations it develops in, but the changes within the cells are very similar.

• Epidemic (AIDS-associated) Kaposi sarcoma. The most common type of KS in the United States is epidemic or AIDS-associated. It develops in people who are infected with HIV (human immunodeficiency virus), the virus that causes AIDS. A person infected with HIV doesn’t necessarily have AIDS, but the virus can be present in the body for many years before causing major illness. The disease known as AIDS begins when the virus has seriously damaged a person's immune system, which means they can get certain types of infections (such as Kaposi sarcoma-associated herpesvirus or KSHV) or other medical complications. KS is considered an AIDS defining illness. This means that when KS occurs in someone infected with HIV, that person officially has AIDS (and is not just HIV-positive). In the United States, treating HIV infection with highly active antiretroviral therapy (HAART) has resulted in fewer cases of AIDS-associated KS. Still, some patients can develop KS in the first few months of HAART treatment. For most patients with HIV, HAART can often keep advanced KS from developing. 
   
• Classic (Mediterranean) Kaposi sarcoma. Classic KS occurs mainly in older people of Mediterranean, Eastern European and Middle Eastern heritage. Classic KS is more common in men than in women. People typically have one or more lesions on the legs, ankles or the soles of their feet. Compared to other types of KS, the lesions in this type do not grow as quickly, and new lesions don’t develop as often. The immune system of people with classic KS is not as weak as it is in those who have epidemic KS, but it may be weaker than normal. Getting older can naturally weaken the immune system a little. When this occurs, people who already have a KSHV (Kaposi sarcoma-associated herpesvirus) infection are more likely to develop KS.
   
• Endemic (African) Kaposi sarcoma. Endemic KS occurs in people living in Equatorial Africa and is sometimes called African KS. Kaposi sarcoma-associated herpesvirus (KSHV) infection is much more common in Africa than in other parts of the world, so the risk of KS is higher. Other factors in Africa that weaken the immune system (such as malaria, other chronic infections and malnutrition) also probably contribute to the development of KS, since the disease affects a broader group of people that includes children and women. Endemic KS tends to occur in younger people (usually under age 40). Rarely a more aggressive form of endemic KS is seen in children before puberty. This type usually affects lymph nodes and other organs and can progress quickly. Endemic KS used to be the most common type of KS in Africa. Then, as AIDS became more common in Africa, the epidemic type became more common.
   
• Iatrogenic (transplant-related) Kaposi sarcoma. When KS develops in people whose immune systems have been suppressed after an organ transplant, it is called iatrogenic or transplant-related KS. Most transplant patients need to take drugs to keep their immune system from rejecting (attacking) the new organ. But by weakening the body’s immune system, these drugs increase the chance that someone infected with Kaposi sarcoma-associated herpesvirus (KSHV) will develop KS. Stopping the immune-suppressing drugs or lowering their dose often makes KS lesions go away or get smaller.    

Signs & Symptoms

There are several signs and symptoms of Kaposi sarcoma.

• It usually appears first as spots (lesions) on the skin. The lesions can be purple, red or brown. KS lesions can be flat and not raised above the surrounding skin (patches), flat but slightly raised (plaques) or bumps (nodules). 
   
• The skin lesions of KS most often develop on the legs or face, but they can also appear in other areas. Lesions on the legs or in the groin area can sometimes block the flow of fluid out of the legs. This can lead to painful swelling in the legs and feet.
   
• KS lesions can also develop on mucous membranes (the inner linings of certain parts of the body) such as inside the mouth and throat and on the outside of the eye and inner part of the eyelids. The lesions are usually not painful or itchy.
   
• KS lesions can also sometimes appear in other parts of the body. Lesions in the lungs might block part of an airway and cause shortness of breath. Lesions that develop in the stomach and intestines can cause abdominal pain and diarrhea.
   
• Sometimes KS lesions bleed. If the lesions are in the lung, it can cause you to cough up blood and lead to shortness of breath. If the lesions are in the stomach or intestines, it can cause bowel movements to become black and tarry or bloody. Bleeding from lesions in the stomach and intestines can be so slow that blood isn’t visible in the stool, but over time the blood loss can lead to low red blood cell counts (anemia). This can cause symptoms like tiredness and shortness of breath.

Diagnosis

Karposi sarcoma (KS) is often found when a person goes to the doctor because of signs or symptoms they’re having. Sometimes KS may be found during a routine physical exam. If KS is suspected, further tests will be needed to confirm the diagnosis. These include: 

• Biopsy. To be sure that a lesion is caused by KS, your doctor will need to take a small sample of tissue from the lesion and send it to a lab to be checked. This is called a biopsy.  For skin lesions, your doctor will perform:
   
  • Punch biopsy. For this, a tool that looks like a tiny round cookie cutter is used to remove a deeper sample of skin. Your doctor rotates the punch biopsy tool on the skin until it cuts through all the layers of the skin. The sample is then removed, and the edges of the biopsy site are stitched together.
     
  • Incisional and excisional biopsies. For these types of biopsies, a surgical knife is used to make an elliptical or circular cut through the full thickness of skin. A wedge or sliver of skin is removed, and the edges of the cut are stitched together. An incisional biopsy removes only part of the tumor. An excisional biopsy removes the entire tumor.
     
• Chest X-ray. Your lungs may be X-rayed to see if KS is there. If the X-ray shows something abnormal, other tests, such as a CT scan, might be needed to tell for sure if it is KS or some other condition. For people known to have KS in the lung, chest X-rays can be used to see how the disease is responding to treatment.
   
• Bronchoscopy. A test that lets the doctor look into the windpipe (trachea) and the large airways of the lungs. This procedure is often done if you’re having problems such as shortness of breath or coughing up blood or if the chest X-ray or CT scan shows something abnormal. Any of these could mean that KS is in the lungs.
   
• Gastrointestinal endoscopy. One or more of these tests might be done when the doctor suspects that KS is in the stomach or intestines and is causing problems.
   
  • Upper endoscopy (also called esophagogastroduodenoscopy or EGD). Used to look at the inner lining of the esophagus, the stomach and the first part of the small intestine. For this procedure, you’re first given drugs to make you sleepy. Then, the doctor guides the endoscope (a thin, flexible, lighted tube with a small video camera on the end) through the mouth and esophagus and into the stomach and small intestine. This lets the doctor see things like ulcers, infections and KS lesions. If an abnormal area is seen, the doctor can use small surgical instruments through the endoscope to biopsy it.
     
  • Colonoscopy. Used to look inside the large intestine (colon and rectum). Before this test can be done, the colon and rectum must be cleaned out to remove any stool. This often means drinking a large amount of a liquid laxative the night before and the morning of the procedure. Just before the procedure, you’ll be given intravenous (IV) medicine to make you relaxed or even asleep (sedation). Then a colonoscope (a long, flexible, tube with a light and video camera on the end) is inserted through the rectum and into the colon. Any abnormal areas seen can be biopsied.
     
  • Capsule endoscopy. This is a way to look at the small intestine. It’s not truly a type of endoscopy since it doesn’t use an endoscope. Instead, you swallow a capsule (about the size of a large vitamin pill) that contains a light source and a very small camera. Like any other pill, the capsule goes through the stomach and into the small intestine. As it travels through the small intestine (usually over about 8 hours), it takes thousands of pictures. These images are transmitted electronically to a device worn around your waist while you go on with normal daily activities. The images can then be downloaded onto a computer, where the doctor can look at them. The capsule passes out of the body through the stool during a normal bowel movement and is discarded. 
     
  • Double balloon enteroscopy. A regular endoscopy can’t look very far into the small intestine because it’s too long and has too many curves. This method gets around these problems by using a special endoscope that is made up of two tubes, one inside the other. For this test, you’re given intravenous (IV) medicine to make you relaxed (sedation), and may even be given general anesthesia (so that you’re asleep). The endoscope is then inserted either through the mouth or the anus, depending on if there is a specific part of the small intestine to be examined. Once inside the small intestine, the inner tube, which has the camera on the end, is advanced about a foot as your doctor looks at the lining of the intestine. Then a balloon at its end is inflated to anchor it. The outer tube is then pushed forward to near the end of the inner tube and is anchored in place with a second balloon. This process is repeated over and over, letting your doctor see the intestine a foot at a time. The doctor can even take a biopsy if something abnormal is seen. This procedure is more involved than capsule endoscopy (and can take hours to complete), but it has the advantage of letting the doctor biopsy any lesions seen.

KS can also affect other organs, such as the liver, spleen, heart or bone marrow. These areas don’t often need to be biopsied in people already known to have KS based on biopsies of other tissues, such as skin, lungs or intestines.

Treatment

KSHV, the virus that causes Karposi, cannot be treated. Once you contract KSHV, you’ll always have it. Treatment for Karposi sarcoma is focused on managing symptoms and treating the cancer. The best approach will depend on your specific diagnosis and the extent of the disease. Surgery is not usually recommended because it’s ineffective at curing the disease and lesions can recur. The following treatment strategies may be used for patients with Karposi sarcoma:

• Improving immune system function. The most effective and important therapy for patients with Karposi sarcoma is addressing the immune deficiency that may allow the cancer to grow.
   
  • For AIDS patients, the same antiretroviral therapy used for AIDS may be all that’s needed to treat Kaposi sarcoma. For transplant recipients, changing or decreasing the dosage of immunosuppressant drugs may be recommended. The top priority in treating Kaposi sarcoma patients is strengthening the immune system. Additional treatments such as chemotherapy are not tolerated for long periods in people with existing immunity concerns.
     
• Local therapies. Some doctors may suggest topical treatments including injection of chemotherapy directly into lesions, cryosurgery (freezing), excisions, phototherapy or local radiation when there are only a few small lesions.
   
• Chemotherapy. Patients who do not see improvement in Kaposi sarcoma after addressing immune deficiencies may require chemotherapy as a follow-up treatment. Chemotherapy is usually administered intravenously, although some oral therapies are now being used.
   
• Immunotherapy. This type of treatment works by activating the immune system’s natural ability to fight cancer. Since it has already proven to be effective in treating many types of cancer, researchers are studying its application in Kaposi sarcoma treatment. Ask your doctor about clinical trials for immunotherapy and other emerging treatment approaches.

Causes & Risk Factors    

Kaposi sarcoma (KS) is caused by infection with a virus called the Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8). KSHV is in the same family as Epstein-Barr virus (EBV), the virus that causes infectious mononucleosis (mono) and is linked to several types of cancer. The human herpes virus 8 causes Kaposi sarcoma. Healthcare professionals believe this virus spreads from person to person through saliva. It also may be passed through blood.

When a healthy person gets the HHV-8 virus, that person's immune system is likely to control it. The virus may stay in the body, but it doesn't cause any problems. If something happens to weaken the immune system, the virus may no longer be controlled. This can lead to Karposi sarcoma.

Other risk factors for Kaposi sarcoma include:

• HIV infection. HIV is the virus that causes AIDS.
   
• Age. Kaposi sarcoma can happen at any age. It's most common in adults between 50 and 70.
   
• Living in certain parts of the world. Karposi sarcoma is rare in the United States. It's most common in the Mediterranean, Eastern Europe and sub-Saharan Africa.
   
• Medicines that weaken the immune system. Some conditions are treated with medicine to control the immune system. Medicine that works in this way is often used after organ transplant surgery.

Screening

With skin self-exams and skin checks by a health care professional like a dermatologist, Kaposi sarcoma can often be found early. When skin cancers are found early, they are likely to be easier to treat.