Introduction

When cells in the body start to proliferate uncontrollably, cancer begins. Almost every cell in the body has the potential to develop into cancer and spread. Cancer cells in the skin or mucous membranes lining the gastrointestinal (GI) tract, from the mouth to the anus, including the stomach and intestines. This malignancy is known as Kaposi sarcoma. It arises from the cells lining blood or lymph arteries. It typically manifests as tumours on the skin or mucosal surfaces. 

However, these tumours can also grow in the lungs, digestive system, or lymph nodes, which are bean-sized collections of immune cells found throughout the body. Kaposi sarcoma (KS) is an angio-proliferative disorder that requires infection with human herpesvirus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV). 

On the skin, the aberrant cells of KS produce tumours characterised by purple, red, or brown blotches. We refer to these afflicted regions as lesions. Most frequently, KS skin lesions appear on the face or legs. When the lesions are in the digestive tract, liver, or lungs, KS can lead to major issues or even death. For instance, KS in the digestive tract may result in bleeding, whilst lung tumours may induce dyspnea.

Depending on whether Kaposi sarcoma is localised or spread in the skin, and if lymph nodes or internal organs are involved, many classification schemes have been used. Systems of staging may also be based on the level of immunosuppression.

The course of Kaposi's sarcoma varies. While some people have significant internal and external diseases, others simply acquire a few mild skin lesions. The latter lesions may cause an organ to haemorrhage, get blocked, or perforate, which could be fatal. Although Kaposi sarcoma cannot be cured, its symptoms can be managed with treatment.

Types of Kaposi sarcoma

KS is a very heterogeneous group of neoplasms that is usually divided by its clinical and epidemiologic characteristics into four types, which are as follows;

Classic Kaposi sarcoma

1. Overview

The majority of elderly males with Mediterranean, Middle Eastern, and Eastern European ancestry have classic Kaposi sarcoma. Men are more likely than women to have classic KS. The incidence of KSHV is significantly higher in many parts of the world. According to some data, populations with high KSHV prevalence most likely contracted the virus as children, perhaps through mother-to-child saliva transmission. 

Classic Kaposi tumours, according to specialists, arise from a weakened immune system, just like other forms of Kaposi sarcoma. The malignancy occurs in the context of a normal, age-related deterioration in immune function, even though these guys may have carried the virus their entire lives.

2. Clinical presentation

Usually, people have one or more lesions on their ankles, legs or foot soles. Lesions in this type of KS do not grow as fast or form new lesions as frequently as those in other forms. Although it may be weaker than usual, the immune system of a person with classic KS is not as compromised as that of people with epidemic KS. The immune system may naturally deteriorate with age. People who already have a KSHV (Kaposi sarcoma-associated herpesvirus) infection are at higher risk of developing KS.

3. Disease course

The single or several lesions have erythematous patches on the lower limbs, and the sarcoma is typically indolent, meaning it grows slowly. Since the immune systems of people with Classic KS are often healthy, early diagnosis and treatment enhance prognosis. Over several years, the lesions get enlarged, and eventually painless and non-itchy, lesions develop throughout the body, mainly on the lower limbs (especially the toes and soles).

4. Management

For those who have already experienced the tumour, routine medical screening, including blood tests, scans, and physical examinations, is required at regular intervals. Due to the small size, the condition may be monitored over time if no symptoms are displayed. 

Surgical excisions are typically used to eliminate localised Kaposi Sarcoma; chemotherapy and immunotherapy may be used for KS that affects many body areas. Radiation therapy or cryotherapy can be helpful if the lesions are limited to a small area. Care after surgery is crucial.

Endemic (African) Kaposi sarcoma

1. Overview

The prevalence of Kaposi sarcoma-associated herpesvirus 8 infection is higher in sub-Saharan Africa. Malnutrition and malaria, which are common in this region of the world, might impair the immune system, which could be the reason for the spread of this disease.

2. Clinical presentation

Endemic African Kaposi sarcoma can be more aggressive than other subtypes and is more likely to occur in people younger than age 40. This type occurs in Africa, independent of HIV infection. There are 2 main forms:

• Prepubertal lymphadenopathic form: It predominantly affects children; primary tumours involve lymph nodes, with or without skin lesions. The course is usually fulminant and fatal
• Adult form: This form resembles classic Kaposi sarcoma

3. Disease course

Similar to classic KS, it manifests as cutaneous (skin-related) lesions grouped throughout the lower limbs, which may cause burning or itching. It can take many different forms, from moderate to fast-moving.

4. Management

The number of lesions, the severity of the disease and its functional effects, and the existence of visceral involvement must all be taken into consideration while treating individuals with endemic KS. Except for the lymphadenopathic form, systemic therapy typically works effectively for endemic African KS.

Epidemic (HIV-associated) Kaposi sarcoma

1. Overview

AIDS-related Kaposi Sarcoma is the most common type of Kaposi Sarcoma diagnosed in the United States. It occurs in people who are infected with HIV, the virus that causes AIDS.

2. Clinical presentation

Kaposi's sarcoma, a vascular tumour that arises from the endothelial cells lining blood arteries, is closely associated with HIV infection. Although it typically manifests as bluish or purplish lesions on the skin, it can damage deeper tissues and organs. One important symptom of AIDS is Kaposi's sarcoma, which frequently appears in patients with significantly compromised immune systems.

3. Disease course

HIV damages white blood cells that fight infections, weakening the immune system. The virus can eventually kill enough cells as it grows and spreads throughout the body, and make the body incapable of fending off diseases, including human herpesvirus 8. HIV develops into AIDS when the body can no longer fend off infections.

4. Management

Antiretroviral therapy has contributed to a decrease in the incidence of Kaposi sarcoma. In certain instances, the immune reconstitution syndrome may include a brief, frequently significant deterioration of the illness. Systemic chemotherapy should be used as a supplementary treatment for these patients.

Iatrogenic (transplant-associated) Kaposi sarcoma

1. Overview

People who have received an organ transplant may be more vulnerable to Kaposi sarcoma and human herpesvirus 8 infection. This occurs from drugs used to stop the body from rejecting the transplanted organ suppress the immune system.

2. Clinical presentation

Internal organs, mucous membranes, and skin can all sustain lesions.

3. Disease course

The degree of immunosuppression determines how the disease behaves. It is important to mention that its relapse is possible.

4. Management

Immunosuppressive medications are required for the majority of organ or bone marrow transplant recipients to prevent the donated organ from being attacked by the immune system. However, an immunocompromised transplant recipient who already has a KSHV infection is at risk for developing Kaposi sarcoma, which raises the danger further because the virus can spread during the organ transplant.

FAQs

What causes Kaposi sarcoma?

Kaposi sarcoma is always caused by a viral infection with human herpesvirus 8, also known as Kaposi sarcoma-associated herpesvirus (KSHV).

What are the risk factors for Kaposi sarcoma?

To develop Kaposi sarcoma, a person must get infected with the Kaposi sarcoma-associated herpesvirus (KSHV). The majority of virus carriers, however, will never develop Kaposi sarcoma. In those with HIV, those who have had organ transplants, or those whose immune systems are compromised for other reasons, such as advanced age, the malignancy is typically brought on by compromised immunity.

What does Kaposi sarcoma look like on your skin?

They usually appear first as purple, red, or brown spots (lesions) on the skin.

Is Kaposi's sarcoma an autoimmune disease?

Kaposi's sarcoma is not an autoimmune disease. It is a type of cancer that usually affects people with weakened immune systems.

Summary

Depending on the patient's demographic and immune condition, Kaposi sarcoma can manifest in a variety of ways. Based on clinical characteristics, it is divided into 4 classes: classic Kaposi sarcoma (lesions on legs), endemic (African) Kaposi sarcoma (attacks the population below 40 and it is more aggressive than other forms), epidemic (HIV-associated) Kaposi sarcoma (arises from a skin layer of arteries associated with HIV), and Iatrogenic (transplant-associated) Kaposi sarcoma (related to the suppressed immune system in patients with organ transplant). Improved results depend on early detection, tailored treatment plans, and addressing underlying immunosuppression (either with HAART or by modifying immunosuppressive medications). To prevent it and get the improved treatment, research into HHV-8 vaccines and targeted medicines is crucial.