Kaposi sarcoma (KS) or Kaposi's sarcoma or is a malignant tumor caused by infection with human herpes virus 8 (HHV8), also known as KS agent. The disease was originally described in 1872 by a Hungarian dermatologist Moritz Kaposi, practicing at the University of Vienna. By 1980s, it was widely known as one of the Acquired Immuno Deficiency Syndrome (AIDS) -defining illnesses. The viral cause of Kaposi sarcoma was discovered in 1994.
The disease presents with erythematous to violaceous cutaneous lesions with or without internal disorders. The systemic disease has 4 subtypes-
- African endemic KS- it was originally found in African men of Sub Saharan origin and now present all over the world. It presents in 2 types- African lymphadenopathic Kaposi sarcoma, which affects children under 10 years of age and aggressively involves the lymph nodes; African cutaneous Kaposi sarcoma, which affects mostly men between 20 to 50 years of age and consists of infiltrative, nodular, vascular masses specially on the extremities.
- Classic KS, affecting middle aged or elderly men who are of Mediterranean, Arabian, Eastern European descent; it occurs most commonly on the soles and toes as violaceous, reddish, or bluish-black macules and patches which spread and get coalesced to form plaques or nodules. Some of these patients may have lesions on their visceras.In most cases surgery is the only option.
- KS in iatrogenically immunosuppressed patients- The tumor is caused either when an HHV 8-infected organ is transplanted into a otherwise healthy human or someone when the transplant recipient already has pre-existing HHV 8 infection.
- HIV/AIDS-related KS
The KS lesions may be solitary, localized or disseminated and can involve lymph nodes, oral cavity, and / or viscera. Its morphology may vary- patch, plaque, macular, nodular, and exophytic.
The African endemic KS and HIV/AIDS-related KS are usually more aggressive. The AIDS-related KS lesions most often rapidly develop and progress to nodules or plaques and affect the face, upper trunk, and oral mucosa. The diagnosis is made with the help of a tissue biopsy and CT Scan/MRI.
Treatment is based on the symptomatology and extent of the disease. Localized cutaneous lesions are treated with intralesional injections of alitretinoin gel or vinblastine, cryotherapy, radiotherapy, topical immunotherapy with Imiquimod, or surgical excision. Internal disease or extensive cutaneous disease may require immunotherapy or intravenous chemotherapy. In case of iatrogenic immunosuppression related KS, the immunosuppressive therapy should be reduced or discontinued. In AIDS-related KS, highly active antiretroviral therapy (HAART) has been seen to be beneficial.