Kaposi Sarcoma: Diagnosis

If your healthcare provider thinks you might have Kaposi sarcoma (KS), certain exams and tests will be needed to be sure. The process starts with your healthcare provider asking you questions. You'll be asked about your health history, your symptoms, risk factors (especially if you might have a weakened immune system, such as due to HIV infection), and family history of disease. 

A physical exam will be done, paying special attention to any lesions (changes, sores, or lumps) on your skin or inside your mouth. Pictures of any lesions may be taken. A digital rectal exam (DRE) might also be done. This is because KS lesions can form inside the rectum. To do this exam, your provider puts a gloved, lubricated finger into your rectum to feel for lesions. Your stool may also be checked for blood.

What tests might I need?

If your symptoms or the exam suggest you might have KS, more tests will be needed. You may have one or more of these tests:

  • Biopsy of suspicious areas

  • Imaging tests

  • Blood tests


Your healthcare provider will likely want to test tiny pieces (called samples) of the changed areas. This is called a biopsy. A biopsy is needed to confirm the diagnosis of KS. Depending on where the area is, different kinds of biopsies might be done.

The area may be in an easy-to-reach place, such as on your skin or inside your mouth. Then part or all of it might be removed with minor surgery. Numbing medicine (local anesthesia) will be used. Then your healthcare provider takes out a tiny piece or all of the lesion.

The area may be inside your body, such as in a lung or in your digestive tract. In this case, it might be biopsied during an endoscopic procedure. Endoscopy is done by putting a long, thin, lighted tube into your body. This allows your healthcare provider to look at the lesions. Tools can be put through the tube to take out samples. For instance, lesions in the lungs can be biopsied during a bronchoscopy. For this, a tube is put down your throat and into your lung. Lesions in the esophagus can be biopsied during an upper endoscopy. In this case, a tube is put down your throat and into your esophagus. These types of procedures are often done while you are under sedation. Sedation is medicine to relax you and make you sleepy during the procedure. Numbing medicine might also be used.

The biopsy samples are sent to a lab. There, a healthcare provider called a pathologist tests them to see if cancer is present and, if so, what kind. (A pathologist has special training in looking at and testing cells to diagnose diseases.)

Imaging tests

If you have symptoms that might be from KS or another serious health problem, imaging tests might be done to look inside your body. For instance, if you have symptoms such as shortness of breath or coughing up blood, you may need a chest X-ray of your lungs.

Other types of imaging tests are not often needed to diagnose KS. But tests such as a CT scan or PET scan may be used after diagnosis to see if the cancer has spread to other parts of your body.

Blood tests

If your healthcare provider thinks you might have KS, you will likely have blood tests. For instance, your blood will be tested to see if you are infected with HIV, the virus that causes AIDS. KS is most common in people who are HIV-positive. If you are HIV-positive, your healthcare provider will check your CD4 level T-cell count and HIV viral load, which can help show how well-controlled the infection is. This might affect your treatment.

Other blood tests can be used to check your overall health and see how well organs such as your liver and kidneys are working.

Getting your test results

When your healthcare provider has your test results, they will contact you. Your provider will talk with you about other tests you may need if Kaposi sarcoma is found. Make sure you understand your test results and what your next steps should be.

Online Medical Reviewer: Amy Finke RN BSN
Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 5/1/2023
© 2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.