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Kaposi Sarcoma

(Kaposi's Sarcoma; Multiple Idiopathic Hemorrhagic Sarcoma)

By

Vinod E. Nambudiri

, MD, MBA, EdM, Harvard Medical School

Reviewed/Revised Dec 2023
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Topic Resources

Kaposi sarcoma is a multicentric vascular tumor caused by herpesvirus type 8. It is categorized into 5 types: classic (sporadic), AIDS-associated (epidemic), non-epidemic, endemic (in Africa), and iatrogenic (eg, after organ transplantation). Diagnosis is by biopsy. Treatment for indolent superficial lesions involves cryotherapy, electrocoagulation, excision, or electron beam radiation therapy. Radiation therapy is used for more extensive disease. In the AIDS-associated form, treatment includes antiretrovirals.

Kaposi sarcoma originates from endothelial cells in response to infection by human herpesvirus type 8 Herpesviruses That Infect Humans Herpesviruses That Infect Humans (HHV-8). Immunosuppression (particularly due to organ transplantation or AIDS) markedly increases the likelihood of Kaposi sarcoma in patients infected with HHV-8.

The tumor cells have a spindle shape, resembling smooth muscle cells, fibroblasts, and myofibroblasts.

Classification of Kaposi Sarcoma

Classic Kaposi sarcoma

This type occurs most often in older (> 60 years) men of Mediterranean, Eastern European, or Ashkenazi Jewish ancestry.

The course is indolent, and the disease is usually confined to a small number of lesions on the skin of the lower extremities; visceral involvement occurs in < 10%.

This type is usually not fatal.

AIDS-associated Kaposi sarcoma (epidemic Kaposi sarcoma)

Multiple cutaneous lesions are typically present, often involving the face and trunk. Mucosal, lymph node, and gastrointestinal (GI) involvement is common. Sometimes Kaposi sarcoma is the first manifestation of AIDS.

Non-epidemic Kaposi sarcoma

An additional type of Kaposi sarcoma that has been increasingly recognized occurs in men who are HIV-negative and who have sex with men (1 Classification reference Kaposi sarcoma is a multicentric vascular tumor caused by herpesvirus type 8. It is categorized into 5 types: classic (sporadic), AIDS-associated (epidemic), non-epidemic, endemic (in Africa)... read more Classification reference ). The reasons for increased prevalence in this group is uncertain and remains an area of ongoing investigation.

Endemic Kaposi sarcoma

This type occurs in Africa independent of HIV infection. There are 2 main forms:

  • Prepubertal lymphadenopathic form: It predominantly affects children; primary tumors involve lymph nodes, with or without skin lesions. The course is usually fulminant and fatal.

  • Adult form: This form resembles classic Kaposi sarcoma.

Iatrogenic Kaposi sarcoma (immunosuppressive Kaposi sarcoma)

This type typically develops several years after organ transplantation. The course is more or less fulminant, depending on the degree of immunosuppression.

Classification reference

  • 1. Vangipuram R, Tyring SK: Epidemiology of Kaposi sarcoma: review and description of the nonepidemic variant. Int J Dermatol 58(5):538-542, 2019. doi: 10.1111/ijd.14080

Symptoms and Signs of Kaposi Sarcoma

Cutaneous lesions are asymptomatic purple, pink, brown, or red macules that may coalesce into blue-violet to black plaques and nodules. Some edema may be present. Occasionally, nodules fungate or penetrate soft tissue and invade bone.

Although less common, visceral involvement most often involves the oral cavity, gastrointestinal (GI) tract, and the lungs. Symptoms depend on specific organ involvement. Mucosal lesions appear as bluish to violaceous macules, plaques, and tumors. GI lesions can bleed, sometimes extensively, but usually are asymptomatic.

Diagnosis of Kaposi Sarcoma

  • Biopsy

Diagnosis of Kaposi sarcoma is confirmed by punch biopsy.

Patients with AIDS or immunosuppression require evaluation for visceral spread by CT of the chest and abdomen.

If CT is negative but pulmonary or GI symptoms are present, bronchoscopy or endoscopy should be considered.

Treatment of Kaposi Sarcoma

  • Surgical excision, cryotherapy, electrocoagulation, intralesional chemotherapy, or possibly topical imiquimod or alitretinoin for superficial lesions

  • Local radiation therapy and chemotherapy for multiple lesions, diffuse involvement, or lymph node disease

  • Antiretroviral therapy with similar local treatments or chemotherapy depending on extent of disease for AIDS-associated Kaposi sarcoma

  • Reduction of immunosuppressants for iatrogenic Kaposi sarcoma

Treatments for classic Kaposi sarcoma and AIDS-associated Kaposi sarcoma overlap considerably.

Indolent lesions often require no treatment. One or a few superficial lesions can be removed by excision, cryotherapy, or electrocoagulation or treated with intralesional vinblastine or interferon alfa. Topical imiquimod or alitretinoin has also been reported to be effective. Multiple lesions, diffuse involvement, and lymph node disease are treated locally with 10 to 20 Gy of radiation therapy and chemotherapy. Recurrence is common, and it is difficult to obtain a complete cure.

AIDS-associated Kaposi sarcoma responds markedly to antiretroviral therapy (ART), probably because the CD4+ count increases and the HIV viral load decreases; however, there is some evidence that protease inhibitors in this regimen may block angiogenesis (although this has not been shown to have beneficial clinical effects in humans).

In patients with AIDS who have indolent local disease, CD4+ counts > 150/mcL, and HIV RNA < 500 copies/mL, intralesional vinblastine can be added. Pomalidomide can also be used for more indolent lesions.

Patients with more extensive or visceral disease can be given pegylated liposomal doxorubicin 20 mg/m2 IV every 2 to 3 weeks. Paclitaxel is an alternative first-line treatment or can be given if pegylated liposomal doxorubicin fails.

Other agents being investigated as adjuncts include interleukin (IL)-12, desferrioxamine, and oral retinoids. Treatment of Kaposi sarcoma does not prolong life in most patients with AIDS because infections dominate the clinical course.

Non-epidemic classic Kaposi sarcoma requires treatment of indolent lesions as described above Treatment Treatment .

Iatrogenic Kaposi sarcoma responds best to stopping immunosuppressants. In patients who have had an organ transplant, reduction of immunosuppressant dosage often results in reduction of Kaposi sarcoma lesions. If dosage reduction is not possible, conventional local and systemic therapies used in other types of Kaposi sarcoma should be instituted. Sirolimus may also improve iatrogenic Kaposi sarcoma.

Endemic Kaposi sarcoma treatment is challenging and typically palliative.

Key Points

  • Consider Kaposi sarcoma in older men, Africans, and patients with organ transplants or AIDS.

  • Test patients with immunosuppression (including AIDS) for metastases.

  • Treat superficial lesions with locally ablative methods.

  • Treat multiple lesions, diffuse involvement, or lymph node disease with local radiation therapy and chemotherapy.

Drugs Mentioned In This Article

Drug Name Select Trade
Velban
Aldara, Zyclara
Panretin
POMALYST
Adriamycin, Adriamycin PFS, Adriamycin RDF, Rubex
Onxol , Taxol
HYFTOR, Rapamune
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