Kaposi sarcoma involving the gastrointestinal tract.

Abstract

Kaposi sarcoma is a low-grade vascular tumor associated with human herpesvirus-8 infection (HHV-8). The first description of this tumor dates back to 1872 and was made by Dr. Moritz Kaposi, a Hungarian dermatologist who described 5 cases of “idio-pathic multiple pigmented sarcomas of the skin.”1 In total, 4 forms of this disease have been described. As HHV-8 has been detected in all 4 forms of Kaposi sarcoma,2 these forms likely represent different manifestations of the same pathologic process. The classical variant of Kaposi sarcoma occurs predominantly in elderly men from Eastern Europe and Mediterranean countries.3–5 This form is not associated with HIV, but it coincides with an altered immune system and malignant diseases. Clinically, this variant is distinguished by multiple red-to-purple nodules on the lower limbs. These nodules slowly grow larger and are subsequently also found in more proximal regions. The tumors are usually asymptomatic and are rarely systemically progressive. The second variant is the lymphadenopathy-associated form of Kaposi sarcoma, also called the endemic or African form. This form is very aggressive6and is often found in South Africa in young Bantu children with local or generalized lymphadenopathy.7Skin lesions are rare in this variant. The third variant is the transplant- or immunosuppression-associated form of Kaposi sarcoma. This form develops between several months to several years after organ transplantation with immunosuppressive therapy. Lesions develop on the skin, but in approximately half of the cases, they are also found in internal organs and lymph nodes.8–10 The fourth variant of Kaposi sarcoma is the AIDS-associated (epidemic) form. This form is found in approximately one fourth of all AIDS patients and is the most common AIDS-associated tumor in the United States. Kaposi sarcoma occurs in AIDS-affected homosexual men 20 times more frequently than in nonhomosexual AIDS patients with the same degree of immunodeficiency. AIDS-associated Kaposi sarcoma has no preferred locations but is widely scattered, and involvement of the lymph nodes and intestine occurs relatively early.3,11