Kaposi's sarcoma (KS) is a type of cancer that arises from the cells that line blood and lymphatic vessels. It appears as abnormal growths or lesions that can develop on the skin, in lymph nodes, in the mouth, and in internal organs. Unlike many cancers that originate in a single area and then spread, Kaposi's sarcoma can cause lesions in multiple parts of the body at the same time. The lesions are usually red, purple, or brown and may be flat or raised.
What Causes Kaposi's Sarcoma?
Kaposi's sarcoma is caused by infection with a virus known as human herpesvirus-8 (HHV-8), also called Kaposi's sarcoma-associated herpesvirus (KSHV). However, not everyone who carries HHV-8 develops the disease. In most people, HHV-8 infection does not lead to KS unless the immune system is weakened.
The virus interferes with normal cellular functions and can promote uncontrolled growth of blood and lymphatic vessel cells under certain conditions. Persistent viral infection together with impaired immunity—such as in HIV infection, organ transplant immunosuppression, or age-related immune decline—creates an environment in which Kaposi's sarcoma can develop.
Who Is at Risk for Kaposi's Sarcoma?
There are several distinct forms of Kaposi's sarcoma, each linked to different risk factors:
•Epidemic (AIDS-related) KS: Most common form worldwide, particularly affecting individuals with HIV infection. The risk increases when HIV weakens the immune system significantly.
•Classic KS: Occurs mainly in older adults of Mediterranean, Middle Eastern, or Eastern European descent. This form is typically slow-growing and less aggressive.
•Endemic KS: Seen in regions of sub-Saharan Africa, even in people without HIV. Children and young adults can be affected.
•Iatrogenic (Transplant-related) KS: Occurs in people who receive long-term immunosuppressive therapy after organ transplantation.
Globally, KS is much more common in populations where HHV-8 infection is widespread. Sub-Saharan Africa has the highest rates of both endemic and HIV-related KS.
How Does Kaposi's Sarcoma Spread?
Kaposi's sarcoma itself is not contagious, but the virus that causes it, HHV-8, can be transmitted between people. Transmission routes include sexual contact, close personal contact involving saliva, and possibly from mother to child. Blood transfusions or transplantation of infected tissue may also spread the virus.
Once a person is infected with HHV-8, it may remain dormant for many years without causing disease. Kaposi's sarcoma usually develops only when the immune system is weakened.
What Are the Typical Symptoms of Kaposi's Sarcoma?
The earliest signs of Kaposi's sarcoma are commonly skin lesions. These lesions may appear as:
* Flat or slightly elevated patches
* Raised nodules
* Red, purple, or brown colored areas
Lesions are most often found on the legs, feet, face, or inside the mouth, but they can also appear in internal organs with no obvious skin change.
Beyond skin involvement, lesions in the gastrointestinal tract may cause abdominal pain or bleeding, and lesions in the lungs may lead to shortness of breath. Lesions can sometimes block lymphatic flow, resulting in painful swelling.
How Is Kaposi's Sarcoma Diagnosed?
Diagnosis of Kaposi's sarcoma begins with a clinical examination of visible lesions. However, a definite diagnosis requires a biopsy, where a small piece of tissue is removed from a lesion and examined under a microscope. Special tests can detect viral proteins such as the latency-associated nuclear antigen (LANA), which helps confirm the presence of HHV-8 in the tumor cells.
In addition to skin biopsy, doctors may use imaging techniques such as X-rays, CT scans, or endoscopy to determine whether the disease has spread internally. Blood tests, including CD4 cell counts in people with HIV, help assess immune status.
Can a Dermatoscope Detect Kaposi’s Sarcoma?
A dermatoscope is a non-invasive tool that magnifies skin lesions and allows visualization of subsurface structures such as vascular patterns and pigmentation. In KS, dermoscopy can reveal features that raise suspicion, but it cannot replace histopathological diagnosis.
When using a high-quality dermatoscope—such as those developed by IBOOLO—clinicians typically look for several "hallmark" signs that suggest KS:
* Polychromatic coloration (a rainbow pattern with multiple colors)
* Reddish-purple or violaceous background
* Irregular or serpentine vascular structures
* Structureless areas corresponding to vascular proliferation
What Treatment Options Are Available for Kaposi's Sarcoma?
Treatment for Kaposi's sarcoma depends on the type of disease, severity of symptoms, and immune status of the patient:
For HIV-associated (Epidemic) KS
The most important treatment is antiretroviral therapy (ART). Effective ART strengthens the immune system, reduces HIV replication, and often leads to regression of KS lesions. In many cases, ART alone may control the disease.
Local Therapies
For limited skin-only disease, doctors may use local treatments such as surgical removal, cryotherapy (freezing), or radiation therapy. These limit or remove specific lesions but do not treat systemic disease.
Chemotherapy and Systemic Therapy
When KS is widespread or affecting internal organs, systemic chemotherapy is often needed. Drugs such as liposomal anthracyclines and paclitaxel are commonly used in more aggressive cases.
Emerging Treatments
Research is ongoing into targeted drugs that inhibit blood vessel growth (anti-angiogenic agents) and immune-modulating therapies that enhance the body's response to the virus and tumor. These new strategies are promising, particularly for disease that is resistant to standard therapy.