Introduction

Kaposi sarcoma is a rare form of cancer that often develops in people with weakened immune systems, particularly those living with acquired immunodeficiency syndrome (AIDS).  It forms red, purple, pink, or brown nodules on the skin, genitals, mouth, lymph nodes, gastrointestinal tract, and lungs.¹ 

Kaposi sarcoma was first described in 1872 by Moritz Kaposi as “idiopathic multiple pigmentation of the skin,” and was subsequently named after him. Over time, doctors learned that this was not simply a skin condition but a cancer involving blood vessel–forming cells. Today, four main types of Kaposi sarcoma are recognised:^2,3

1. Classic (sporadic). It occurs mostly in older men of Mediterranean or Eastern European descent
2. Endemic (African). It is more common in sub-Saharan Africa, sometimes affecting children
3. Iatrogenic (transplant-related). It develops in people taking immunosuppressant drugs after organ transplantation
4. Epidemic (AIDS-related). It is the most common and aggressive form, often involving multiple organs

When Kaposi sarcoma spreads to the lungs, it is known as pulmonary Kaposi sarcoma, a serious condition that can interfere with breathing and be life-threatening if not treated promptly. Here we will review what causes this disease, how it presents, the methods doctors use to diagnose it, and the current options for treatment.

Causes of pulmonary kaposi sarcoma

Kaposi sarcoma is associated with human herpesvirus 8 (HHV-8) infection. The virus spreads primarily through saliva, but can also be transmitted via sexual contact and from a mother to her child, leading to the formation of tumours. HHV-8 damages cellular DNA, causing uncontrolled cell growth and the development of reddish-purple lesions on the skin, mouth, nose, and throat.⁴ Pulmonary involvement can be indicated by symptoms such as:

• Coughing (sometimes with blood)
• Shortness of breath
• Chest pain or tightness
• Wheezing or airflow obstruction

Because these symptoms overlap with other lung infections, pulmonary Kaposi sarcoma can be challenging to diagnose without further testing.

Symptoms and clinical presentation

Pulmonary Kaposi sarcoma may look similar to pneumonia, which makes it easy to misdiagnose. Both conditions can cause cough, fever, and difficulty breathing. However, unlike pneumonia, KS results from tumours in the lungs rather than an infection caused by bacteria or viruses.⁵ The most common symptoms include:⁶

• Cough
• Shortness of breath (Dyspnoea)
• Fever
• Night sweats
• Hemoptysis (coughing up blood)
• Airflow obstruction

Diagnosis of pulmonary kaposi sarcoma

Doctors use several steps to diagnose pulmonary Kaposi sarcoma. Physical examinations are often first. They focus on identifying characteristic lesions on the skin, mouth, or internal signs like enlarged lymph nodes. Then, imaging tests, such as computed tomography (CT) scans and X-rays, help determine the extent of the disease and if it has spread to internal organs like the lungs. Finally, transbronchial biopsies, or biopsies of the tumour, are taken to confirm the presence of the cancer and its corresponding type.⁶ 

The diagnosis of pulmonary Kaposi Sarcoma in people with AIDS is often clinical and relies on mucocutaneous findings, CT scans, and bronchoscopy. Affected individuals typically experience respiratory symptoms such as cough, breathing difficulty, fatigue, and sometimes respiratory failure. Chest CT scans show hilar densities, nodular patterns, and interstitial thickening, with pleural effusions also being a possibility. Bronchoscopy reveals endobronchial lesions. Endobronchial lesions are characterised by red and violet papules or macules located in the bifurcation of the bronchial tree.⁶ Biopsies are reserved for situations where the clinical presentation is unclear because of the haemorrhagic risk associated with the angioproliferative nature of the tumour.⁷ Sequential thallium and gallium scans can also be used to help diagnose pulmonary Kaposi sarcoma and distinguish it from other common AIDS-associated chest complications.⁸

Management of pulmonary kaposi sarcoma

The main goal of treatment is to control the disease, relieve symptoms, and improve survival.  Highly active antiretroviral therapy (HAART) is the most common treatment, leading to lesion regression.⁹ After optimising HAART, systemic chemotherapy can be used, with studies showing that combination chemotherapy is more effective than single-agent options like liposomal doxorubicin, liposomal daunorubicin, paclitaxel, or etoposide. Emerging therapies,  including interleukin 12 and angiogenesis inhibitors,  which block the tumour’s ability to form new blood vessels, are also under investigation.¹⁰ Oxygen therapy, treatment of secondary infections, and palliative care are also important for maintaining quality of life.

Summary

Pulmonary Kaposi sarcoma is a rare form of tumour primarily affecting individuals with weakened immune systems, including those with AIDS. It is caused by an infection with HHV-8. It causes tumours in the lungs that interfere with breathing and can resemble pneumonia. The affected individuals present symptoms such as coughs, shortness of breath and fatigue. Diagnosis usually involves imaging, bronchoscopy, and sometimes biopsies. Treatment combines antiretroviral therapy and chemotherapy, with the goal of improving survival through early detection and effective treatment plans. 

FAQs

Is pulmonary kaposi sarcoma contagious?

No. While the underlying virus (HHV-8) can be transmitted, the cancer itself is not contagious. 

How is pulmonary kaposi sarcoma different from pneumonia?

Both conditions can cause cough and difficulty breathing, but pneumonia is an infection caused by bacteria or viruses, while pulmonary Kaposi sarcoma is a cancer caused by HHV-8. Imaging tests and bronchoscopy help distinguish between the two.

Can pulmonary kaposi sarcoma be cured?

Currently, there is no cure. However, treatment with antiretroviral therapy and chemotherapy can control the disease and improve survival. 

How long can someone live with pulmonary Kaposi sarcoma?

Life expectancy depends on the stage of the disease, immune status, and response to treatment.

Can kaposi sarcoma affect people without HIV?

Yes, although it is much less common.

What should I do if I think I have symptoms of pulmonary kaposi sarcoma?

Seek medical care immediately, especially if you are living with AIDS or another immune condition.