Kaposi's sarcoma is a relatively rare cancer disease. Its importance grows in context of the worldwide AIDS epidemics.
Kaposi's sarcoma arises from cells of the lymphatic vessels. The cause is infection with certain subgroups of herpesviruses that is typical in severely immunocompromised patients such as patients with AIDS. Viral particles attack and damage the cells causing malignant changes and tumor development. Close relationship between HIV and herpesvirus presence is emphasized by fact that both viruses are sexually transmitted. In addition to AIDS, Kaposi's sarcoma may develop in chronic drug abusers and in patients during a long-term immunosuppressive therapy.
Kaposi's sarcoma usually grows on the skin and mucous membranes, for example in the oral cavity. It is richly supplied with blood and it looks like reddish, brown or dark blue spot that slightly protrudes above the skin. As the tumor grows from the lymph vessels, it can cause local damage of lymphatic system. The disruption of lymphatic drainage may result in local swelling (lymphedema). In some cases, Kaposi's sarcoma occurs even deep within the body, such as in digestive tract and respiratory system. In such case, it may cause diarrhea, blood in stool, cough and coughing up blood. Approximately 10% of patients with Kaposi's sarcoma may develop the so-called Castleman's disease.
The diagnosis is confirmed by histological examination of a tissue sample obtained from the lesion. If there is a suspicion of Kaposi’s sarcoma, it is reasonable to exclude AIDS or other conditions related to weakened immunity.
The therapy of Kaposi's sarcoma is difficult. If the tumor mass is located in an accessible place, it can be removed surgically. The treatment may be supported by chemotherapy and special drugs to improve the functions of the immune system. Any underlying condition, when confirmed, should be treated as well.