(See also Overview of Skin Cancer Overview of Skin Cancer Skin cancer is the most common type of cancer and commonly develops in sun-exposed areas of skin. Skin cancers can be found on any location of the body but are most commonly diagnosed on the... read more .)
Kaposi sarcoma originates from endothelial cells in response to infection by human herpesvirus type 8 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)
This type is the most common AIDS-associated cancer Cancers Common in Patients with HIV Infection AIDS-defining cancers in patients infected with HIV are Kaposi sarcoma Lymphoma, Burkitt (or equivalent term) Lymphoma, immunoblastic (or equivalent term) Lymphoma, primary, of central nervous system read more and is more aggressive than classic 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 ). 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.
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
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.
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.
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
|Adriamycin, Adriamycin PFS, Adriamycin RDF, Rubex
|Onxol , Taxol