Introduction to Kaposi’s sarcoma

Kaposi’s sarcoma, a cancer of the lymphatic cell wall, affects tissues under the skin or mucous membranes that line the mouth, nose, and anus. In recent years, the incidence of Kaposi’s sarcoma has risen dramatically along with the incidence of human immunodeficiency virus (HIV) infection. It’s now the most common HIV-related cancer.
Kaposi’s sarcoma causes structural and functional damage. It progresses aggressively, involving the lymph nodes, the viscera and, possibly, GI structures.

Etiology
The exact cause of Kaposi’s sarcoma is unknown, but the disease may be related to immunosuppression. Genetic or hereditary predisposition is also suspected.

Signs and symptoms

The initial sign of Kaposi’s sarcoma is one or more obvious lesions in various shapes, sizes, and colors (ranging from red-brown to dark purple) that appear most commonly on the skin, buccal mucosa, hard and soft palates, lips, gums, tongue, tonsils, conjunctivae, and sclerae.
With advanced disease, the lesions may join, becoming one large plaque. Untreated lesions may appear as large, ulcerative masses.

                           Kaposi's Sarcoma Seen as a tumor on the roof of the mouth

                                                    Kaposi Sarcoma Affecting the skin
Other signs and symptoms include:

• a history of HIV infection
• pain (if the sarcoma advances beyond the early stages or if a lesion breaks down or impinges on nerves or organs)
• edema from lymphatic obstruction
• dyspnea (in cases of pulmonary involvement), wheezing, hypoventilation, and respiratory distress from bronchial blockage.
• The most common extracutaneous sites are the lungs and GI tract (esophagus, oropharynx, and epiglottis).

Signs and symptoms of disease progression and metastasis include severe pulmonary involvement and GI involvement leading to digestive problems.

Diagnosis
The diagnosis is made following a tissue biopsy that identifies the lesion’s type and stage. Then a computed tomography scan may be performed to detect and evaluate possible metastasis.

Treatment
Treatment isn’t indicated for all patients with Kaposi’s sarcoma. Indications include cosmetically offensive, painful, or obstructive lesions of rapidly progressing disease.
Radiation therapy, chemotherapy, and biotherapy with biological response modifiers are treatment options. Radiation therapy alleviates signs and symptoms, including pain from obstructing lesions in the oral cavity or extremities and edema caused by lymphatic blockage. It may also be used for cosmetic improvement.
Combinations of three or more anti-HIV drugs may control HIV as well as flatten, shrink, or fade Kaposi’s sarcoma lesions.
A new treatment uses 9 cis retinoic acid, a derivative form of vitamin A that can be applied directly to skin lesions.
Chemotherapy includes combinations of doxorubicin, vinblastine, vincristine, and etoposide to treat internal, widespread Kaposi’s sarcoma. Paclitaxel may be used when other chemotherapeutic drugs fail. Liposomal drugs may also be used.
Biotherapy with interferon alfa-2b may be administered for HIV-related Kaposi’s sarcoma. The treatment reduces the number of skin lesions, but is ineffective in patients with advanced disease.