Endemic Kaposi sarcoma

Other Names: African Kaposi sarcoma; African/endemic Kaposi sarcoma Kaposi's sarcoma (KS) is a type of cancer that can form masses in the skin, lymph nodes, or other organs. The skin lesions are usually purple in color. They can occur singularly, in a limited area, or be widespread. Kaposi’s sarcoma (KS) is the most common tumor in HIV-infected individuals in Africa KS is a vascular tumor which arises in multifocal sites. The skin is most commonly involved, though virtually any organ, except perhaps the brain can be involved.

An example of Kaposi's sarcoma

An HIV-positive person presenting with a Kaposi's sarcoma lesion with an overlying candidiasis infection in their mouth

Risk factors

Kaposi's sarcoma remains the most common cancer in Sub-Saharan Africa and the second most common cancer in HIV-infected patients worldwide. Since the introduction of highly active antiretroviral therapy (HAART), there has been a decline in its incidence. However, Kaposi's sarcoma continues to be diagnosed in HIV-infected patients. Risk factors include poor immune function, either as a result of disease or specific medications, and chronic lymphedema.

Cause

Kaposi's sarcoma-associated herpesvirus (KSHV), also called HHV-8, is present in almost 100% of Kaposi sarcoma lesions, whether HIV-related, classic, endemic, or iatrogenic.

Classifications

Kasposi’s sarcoma has four classifications, based on varying clinical characteristics and risk factors

• Classic Kasposi’s sarcoma affects elderly, immunocompetent individuals of

Mediterranean or Eastern European descent. It is a slow-progressing and relatively benign form of the cancer.

• Endemic or African Kaposi’s sarcoma is most common in Central and Eastern

Africa and primarily affects adults

• Iatrogenic Kaposi’s sarcoma is found in populations with compromised immune systems, primarily in patients who have received organ transplants.
• AIDs-Kaposi’s sarcoma develops in populations infected with HIV-AIDS. In Western countries,

AIDS-KS is most commonly found in HIV-infected men who have sex with men.

Signs and symptoms

KS lesions are nodules or blotches that may be red, purple, brown, or black, and are usually papular.

They are typically found on the skin, but spread elsewhere is common, especially the mouth, gastrointestinal tract and respiratory tract. Growth can range from very slow to explosively fast, and is associated with significant mortality and morbidity.

The lesions are painless, but become cosmetically disfiguring or interruptive to organs.

Diagnostics:

First and foremost is the clinical picture of erythematous violaceous cutaneous lesions that canbe macular, patch, plaque, nodular or exophytic. The lesions can be solitary, localized or disseminated. This in the background of HIV/AIDS should alert the physician to the diagnosis of KS. The presence of local/regional lymphoedema almost gives away the diagnosis. However tissue confirmation is mandatory before instituting any form of therapy.

Local punch biopsy or rarely, excision biopsy are all that are required for a skin biopsy.

Lymphnode excision can also be done in predominantly nodal lesions. Endoscopic biopsies may berequired for lesions presenting solely in visceral lumens. Tissues should be subjected to pathologic examination by an experienced histopathologist.

Treatment

It has been noted that highly active antiretroviral therapy (HAART) alone improves the outcome of HIV associated KS

Patients with aggressive forms of KS are commonly treated with paclitaxel or doxorubicin(orliposomal doxorubicin), bleomycin and vinblastine or vincristine (ABV). The ABV regimen hasbeen shown to give better response rates than BV (Bleomycin, vinblastine / vincristine) alone. This regimen was however not very popular because of toxicity [[Gemcitabine monotherapy]] has been suggested as an alternative option in patients previously treated with ABV

Paclitaxel, with response rates ranging from 59%-71% when given without HAART (12,13), is considered the most attractive agent since it is effective and tolerable over long-term administration especially when combined with growth factors (13,14). Paclitaxel for this reason should be added to the essential medicines list.

Alpha interferon and radiotherapy have also been used in the management of AIDS-associated KS. Their use has been limited by the toxicity profile. Rapamycin was noted to be safe in HIV infected individuals with KS and can in some cases induce tumor regression

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Pazopanib (Brand name: Votrient)Advanced soft tissue sarcoma (STS) who have received prior chemotherapy.

Additional images

• 
  Micrograph of promontory sign in Kaposi's sarcoma in patch stage. Dilated irregular vascular channels surround a pre-existing vessel.<ref name=Soyer2011/>
• 
  Micrograph of plaque stage, with bizarre vessels dissecting the upper dermis. There is erythrocyte extravasation and hemosiderin pigmentation.<ref name=Soyer2011/>
• 
  Micrograph of tumor stage. Well-circumscribed spindle-cell tumor. Erythrocytes lie within poorly defined slit-like vascular spaces.<ref name=Soyer2011/>

NIH genetic and rare disease info

• NIH info on Endemic Kaposi sarcoma

Endemic Kaposi sarcoma is a rare disease.