Diagnosing Kaposi Sarcoma

NYU Langone doctors are experienced in recognizing and diagnosing Kaposi sarcoma. This type of cancer is caused by human herpesvirus 8, also called Kaposi sarcoma–associated herpesvirus.

Human herpesvirus 8 infects the sheet-like epithelial cells that line blood vessels and lymph vessels. This lining is also called the endothelium. The infection can cause the epithelial cells to divide uncontrollably in several places in the body at once.

Risk Factors for Kaposi Sarcoma

People with healthy immune systems are less likely to develop Kaposi sarcoma compared with people who have weakened immune systems. Specifically, people with human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) are at an increased risk of developing AIDS-related Kaposi sarcoma.

Other risk factors include taking immunosuppressive medications to help prevent the body from rejecting an organ after a transplant. Additionally, people older than age 60 who are of Mediterranean, Eastern European, or Middle Eastern descent, as well as those living in sub-Saharan Africa, seem to be more susceptible to the infection.

Preventing Kaposi Sarcoma

People who are infected with HIV can take precautions to reduce the risk of developing Kaposi sarcoma.

HIV weakens the immune system by attacking T cells, white blood cells that help fight infection. Antiretroviral therapy can boost the immune system. This treatment raises levels of CD4, which is a type of T cell that can help a person reduce the risk of developing lesions from human herpesvirus 8.

Symptoms of Kaposi Sarcoma

Kaposi sarcoma cells can spread to the skin or mucosa—the tissue that lines the inner surfaces of the body, such as the mouth, throat, and gastrointestinal tract—where they form larger cancerous lesions.

On the skin, Kaposi sarcoma typically appears as painless, reddish brown tumors or patches. They are often located behind the ears, around the genital area, or on the lower legs, feet, trunk, and nose.

Tumors in the digestive tract—including in the esophagus, stomach, intestines, and anus—may sometimes cause abdominal pain or bleeding that darkens stool. Lesions that form in the lungs can lead to coughing and difficulty breathing.

Tumors can also develop in the lymph nodes—small glands that produce and store lymphocytes, which are white blood cells that help fight infection—causing them to swell. These tumors may press on or grow into nearby lymph vessels, which carry fluid absorbed from tissues and organs and carry infection-fighting white blood cells throughout the body. Lymph fluid may build up, leading to swelling, reduced range of motion, and discomfort in the arms and legs. This condition is called lymphedema.

Diagnosing Kaposi Sarcoma

To diagnose Kaposi sarcoma, NYU Langone doctors may conduct a medical history, physical exam, biopsy, and other tests.

Medical History and Physical Exam

Your doctor may ask about sexual activity, whether you have had an organ transplant, and if you have any skin lesions or other symptoms, such as breathing problems or blood in the stool.

During a physical exam, the doctor may examine parts of the body—such as the mouth, the lower legs, and the genital area—where Kaposi sarcoma tumors tend to develop. He or she may also conduct a fecal occult blood test to check for blood in the stool that is not visible to the naked eye.

If you have HIV, NYU Langone doctors recommend having an annual physical exam, in which your physician looks for Kaposi sarcoma lesions and asks about symptoms of the cancer to determine whether further testing is needed.

Skin Biopsy

Doctors typically perform a biopsy, in which they remove a small amount of tissue from the skin lesion for examination under a microscope, to diagnose Kaposi sarcoma. Although skin lesions in people with HIV infection and low CD4 levels may indicate Kaposi sarcoma is present, your doctor may want to rule out other problems, such as a bacterial skin infection. A pathologist—a specialist who studies diseases under a microscope—can usually make this distinction.

A skin biopsy is an in-office procedure usually performed with local anesthesia. The doctor may use a special blade that resembles a small cookie cutter to perform what is called a “punch” biopsy. He or she removes a portion of the suspicious lesion then stitches the skin together.

Another option is to perform an excisional biopsy, in which doctors use a scalpel to completely remove the growth, along with some healthy skin. Stitches are used to close the wound.

Chest X-rays or CT Scans

Doctors may recommend a chest X-ray or CT scan in people who have skin lesions confirmed to be Kaposi sarcoma and who are coughing or having trouble breathing.

An X-ray produces images of structures inside the body using a small amount of radiation. A CT scan is a form of X-ray that uses a computer to create cross-sectional pictures of tissues and organs in greater detail than a standard X-ray.

These imaging tests can help doctors determine if there are tumors in the lungs. They also enable doctors to determine whether symptoms are being caused by a lung infection, such as pneumonia, which commonly affects people who have HIV.


If a chest X-ray or CT scan reveals tumors in the lungs, your doctor may perform a bronchoscopy to locate tumor tissue in the airway.

During this procedure, the doctor inserts a bronchoscope—a long, flexible tube with a camera on the end—through the nose or mouth and into the airway in order to see the tumor. He or she then threads surgical instruments, such as small forceps or needles, through the bronchoscope to remove tissue or liquid. Sometimes doctors use fluoroscopy, an imaging technique that uses two-dimensional X-rays, to guide the bronchoscopy.

A bronchoscopy requires sedation or general anesthesia. After the sedation or anesthesia wears off, you can go home.

Upper Endoscopy

Doctors may recommend an upper endoscopy for people with Kaposi sarcoma skin lesions who also have abdominal pain or blood in the stool.

An upper endoscopy is used to examine the lining of the esophagus, stomach, and the first part of the small intestine. During the procedure, the doctor inserts an endoscope—a thin, lighted tube with a camera on the end—through the nose or mouth into the esophagus. The endoscope is then guided through the stomach into the first part of the intestine.

If the doctor sees any lesions in the lining of the stomach or small intestine, he or she can perform a biopsy, in which small surgical tools are inserted through the endoscope to remove a fragment of tissue. It is then checked for signs of cancer under a microscope.

This procedure requires sedation to help you relax. You can usually return home as soon as the sedation wears off. You may notice some discomfort in your throat for a few days following an upper endoscopy.


A colonoscopy enables your doctor to examine the entire colon and rectum. It also allows him or her to identify and biopsy suspicious growths or tissue.

Prior to the test, you may receive an intravenous sedative. During the colonoscopy, your doctor threads a narrow, flexible tube called a colonoscope into the rectum and through the entire colon, or large intestine. A small camera at the tip of the colonoscope allows the doctor to view and examine the lining of the colon and rectum. Small tissue samples of suspicious lesions can be taken during the procedure.

Because of the medication used to relax you during a colonoscopy, someone needs to escort you home afterward.

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