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Kaposi sarcoma (; KS) is a tumor caused by infection with human herpesvirus 8 (HHV8), also known as Kaposi sarcoma-associated herpesvirus (KSHV) or KS agent. It was originally described by Moritz Kaposi, a Hungarian dermatologist practicing at the University of Vienna in 1872. It became more widely known as one of the AIDS-defining illnesses in the 1980s. The viral cause for this cancer was discovered in 1994. Although KS is now well-established to be caused by a viral infection, there is widespread lack of awareness of this even among persons at risk for KSHV/HHV-8 infection. Kaposi sarcoma (KS) is a systemic disease that can present with cutaneous lesions with or without internal involvement. Four subtypes have been described: Classic KS, affecting middle aged men of Mediterranean descent; African endemic KS; KS in iatrogenically immunosuppressed patients; and AIDS-related KS. The erythematous to violaceous cutaneous lesions seen in KS have several morphologies: macular, patch, plaque, nodular, and exophytic. The cutaneous lesions can be solitary, localized or disseminated. KS can involve the oral cavity, lymph nodes, and viscera. Classic KS tends to be indolent, presenting with erythematous or violaceous patches on the lower extremities. African endemic KS and AIDS-related KS tend to be more aggressive. The AIDS-related KS lesions often rapidly progress to plaques and nodules affecting the upper trunk, face, and oral mucosa. The diagnosis can be made with a tissue biopsy and, if clinically indicated, internal imaging should be done. Once the diagnosis of KS has been made, treatment is based on the subtype and the presence of localized versus systemic disease. Localized cutaneous disease can be treated with cryotherapy, intralesional injections of vinblastine, alitretinoin gel, radiotherapy, topical immunotherapy (Imiquimod), or surgical excision. Extensive cutaneous disease and/or internal disease may require intravenous chemotherapy and immunotherapy. Discontinuation or reduction of immunosuppressive therapy is recommended when KS arises in the setting of iatrogenic immunosuppression. However, with AIDS-related KS, highly active antiretroviral therapy (HAART) has been shown to prevent, or induce regression of, KS. Some AIDS patients have complete resolution of the lesions and prolonged remission while continuing the therapy. Therefore, HAART should be considered first-line treatment for these patients, though they may require other treatments at the same time. ==Classification== The Kaposi's sarcoma-associated herpesvirus (KSHV), also called HHV-8, is responsible for all varieties of KS. Since Moritz Kaposi first described this malignant neoplasm, the disease has been reported in five separate clinical settings, with different presentations, epidemiology, and prognoses.〔 All of these forms are infected with KSHV and are different manifestations of the same disease but have differences in clinical aggressiveness, prognosis and treatment. * ''Classic Kaposi sarcoma'' most commonly appears early on the toes and soles as reddish, violaceous, or bluish-black macules and patches that spread and coalesce to form nodules or plaques.〔James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. ISBN 0-7216-2921-0.〕 A small percentage of these patients may have visceral lesions. In most cases the treatment involves surgical removal of the lesion. The condition tends to be (indolent ) and chronic, affecting elderly men from the Mediterranean region, or of Eastern European descent. Countries bordering the Mediterranean basin have higher rates of KSHV/HHV-8 infection than the remainder of Europe. * ''Endemic KS'', which has two types. Although this may be present worldwide, it has been originally described later in young African people, mainly from sub-Saharan Africa. This variant is not related to HIV infection and is a more aggressive disease that infiltrates the skin extensively. * * African lymphadenopathic Kaposi sarcoma'' is aggressive, occurring in children under 10 years of age, presenting with lymph node involvement, with or without skin lesions.〔 These lesions are not related to HIV infection. * * ''African cutaneous Kaposi sarcoma'' presents with nodular, infiltrative, vascular masses on the extremities, mostly in men between the ages of 20 and 50, and is endemic in tropical Africa.〔 These lesions are not related to HIV infection.〔〔 * ''Immunosuppression-associated Kaposi sarcoma'' had been described, but only rarely until the advent of calcineurin inhibitors (such as ciclosporines, which are inhibitors of T-cell function) for transplant patients in the 1980s, when its incidence grew rapidly. The tumor arises either when an HHV 8-infected organ is transplanted into someone who has not been exposed to the virus or when the transplant recipient already harbors pre-existing HHV 8 infection. Unlike classic Kaposi sarcoma, the site of presentation is more variable.〔 * ''AIDS-associated Kaposi sarcoma'' typically presents with cutaneous lesions that begin as one or several red to purple-red macules, rapidly progressing to papules, nodules, and plaques, with a predilection for the head, back, neck, trunk, and mucous membranes. In more advanced cases, they can be found in the stomach and intestines, the lymph nodes, and the lungs.〔 KS-AIDS stimulated the greatest interest as one of the first illnesses associated with AIDS, and was first described in 1981. It is over 300 times more common in AIDS patients than in renal transplant recipients. In this case, HHV 8 is sexually transmitted among people also at risk for sexually transmitted HIV infection. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kaposi's sarcoma」の詳細全文を読む スポンサード リンク
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