Kaposis sarcoma: Description:
Kaposis sarcoma (KS) is a vascular neoplasm of the skin which can also involve any organ. There are several subtypes of KS and have been found to be associated with a virus known as Human Herpesvirus-8 (HHV-8). While everyone with KS also has HHV-8, not everyone with HHV-8 has or develops KS.
Classic KS: This is seen most often in middle aged to elderly men of Southern Mediterranean or Eastern European heritage. It is seen predominantly on the legs but may also occur in the intestinal viscera. Early lesions appear like reddish, bluish or violaceous bumps on the feet and or toes. If left untreated these lesions may join together to form nodules or plaques and at this stage may cause swelling of the affected limb. This can be progressive with gradual spread of the lesions to other parts of the body.
African Cutaneous Kaposis sarcoma: This form occurs is endemic to tropical Africa and occurs primarily in men between 20 and 50 years of age. Patients develop vascular masses that are nodular and infiltrating. While it can have aggressive skin involvement the internal involvement is usually mild.
African Lymphadenopathic KS: This form may or may not have skin involvement but instead attacks the lymph nodes and lymph system. It generally occurs in children of tropical Africa under the age of 10 years. It has an aggressive nature and its victims usually die within 2 years.
AIDS-Associated Epidemic KS: In those with advanced HIV disease this can develop as red to purple macules that can rapidly spread to papules, nodules and plaques. It usually appears on the head and neck area first and can spread rapidly if the underlying Immunosuppression is not addressed. While this form has been common in HIV infected individuals, with the onset of aggressive HIV treatment it has shown a reduction in its prevalence. It is almost exclusively seen in homosexual or bisexual men.
Nonepidemic Gay related KS: There is a type of KS that develops in homosexual men who have no signs or symptoms of HIV infection. This type of Kaposi's sarcoma progresses slowly, with new lesions appearing every few years. The lesions are most common on the arms, legs, and genitals, but can develop anywhere on the skin.
Immunosuppression or Iatrogenic-Associated KS: This type is related to immunosuppression created artificially by medications such as those taken to prevent transplanted organ rejection. This type resembles the Classic KS form but its presentation can be much more variable.
When the viscera are involved it is most common in the intestines with the small intestine being the most frequently affected. However other organs can also be affected such as the lungs, heart, liver, lining of the mouth, conjunctiva, adrenal glands and of course the lymph vessels and nodes. In advanced disease there is also bone involvement. Kaposi's sarcoma is also associated with an increase risk of other malignancies such as lymphomas, leukemias, and myeloma. The risk of lymphoreticular malignancies is about 20 times greater in the Kaposis sarcoma population as compared to those with out the disease.
There are no general symptoms of early KS. In the epidemic form, Kaposis sarcoma may be the first sign of AIDS, or, the first lesion may follow an illness of months or years. During this time, the patient may have had non-specific symptoms such as fever, weight loss and sweating. Possibly there were other illnesses
, such as lymphoma
or tuberculosis, before the first KS lesion developed.
Once the disease occurs, symptoms relate to the site of involvement. Early and more advanced skin lesions are usually only mildly uncomfortable, although painful ulcers may occur.
Lesions in the gastrointestinal tract are very common but rarely cause significant symptoms. Early lesions in the lung have no symptoms either, but severe lung involvement produces a profound air hunger.
KS is not considered curable. Neither surgical removal of the first-detected lesion nor obtaining a complete remission of multiple sites with chemotherapy or other techniques results in cure. Long-term survival does occur both with or without treatment, however.
Survival in classic KS is usually years and sometimes decades. Some patients with AIDS-related Kaposis sarcoma are still alive after 10 years, though most survive only a few years and treatment decisions are usually aimed at palliation.
All forms of KS are sensitive to radiation therapy. Radiation is especially useful for lesions that are cosmetically disturbing, painful, involve the mouth extensively, block lymphatics, bleed, or protrude from the skin. Response rates are quite high and treatment is well tolerated.
Chemotherapy can be used in treatment but there is concern that aggressive treatment might further depress the immune system. The disease does respond to chemotherapy, both with single agents and combinations of drugs.
KS is one of the few tumors that respond to local injections of chemotherapy. Many anticancer drugs cause intense local damage if they are accidentally injected into tissue. This undesirable effect has been used in a positive way to treat skin lesions.
Biological therapy involves immunologic treatment of KS primarily with the interferons, mainly alpha. Other agents, especially interleukin-2 are being studied.
Causes and Risk factors:
The epidemic KS, occurring as a disease that accompanies AIDS, is thought to have a cause - the virus named HIV (Human Immunodeficiency Virus). If given a blood test for HIV, nearly all patients with epidemic KS will show evidence of being infected.
Various ideas have been advanced to explain how this virus causes Kaposis sarcoma. One theory is that it causes a normal cell to become malignant either directly or by initiating a chain of events. Various agents that may be involved in such a change have been identified.
Yet another idea has to do with the body's T cells, some of which hunt for malignant cells that have developed spontaneously and kill them off before they can become cancers. The T cell is known to be infected with the virus and cannot kill the malignant cells.
1. HIV enzyme-linked immunosorbent assay
2. HIV Western blot
Imaging Studies: Imaging studies are generally not necessary, unless orbital or disseminated Kaposi sarcoma is suspected.
Procedures: Cutaneous or conjunctival biopsy of the lesion may be necessary for a definitive diagnosis.
Histologic Findings: All 4 variants of Kaposi sarcoma demonstrate similar histologic findings of tissue, containing endothelium-lined vascular channels and proliferation of spindle-shaped cells surrounded by inflammatory cells. Often, an increased angiogenesis with erythrocyte extravasation is present. Dugal et al described 3 histologic types of Kaposi sarcoma, which probably represents different stages along a continuum.
Type I: Thin, dilated vascular channels are lined by flat endothelial cells with lumen-containing erythrocytes. The cells have flat endothelial fusiform nuclei and scanty cytoplasm. Moderate mononuclear cell infiltrate surround these abnormal vessels. No spindle cells or slit spaces are observed.
Type II: Plump, fusiform endothelial cells line thin, dilated empty vascular channels. Many of these cells have hyperchromatic nuclei. The inflammatory infiltrate of macrophages, plasma cells, and lymphocytes is sparse. Foci of a few immature spindle cells and early slit vessels are present.
Type III: Large aggregates of densely packed spindle cells with hyperchromatic nuclei, occasional mitotic figures, and abundant slit spaces often contain erythrocytes. Inflammatory cells are scant.
Medicine and medication:
The chemotherapy drugs Taxol® (paclitaxel) and Taxotere® (docetaxel) appear to be active treatments for recurrent or refractory Kaposi's sarcoma.
Taxol has been found to cause tumors to shrink significantly in the majority of patients with advanced Kaposi's sarcoma who have not responded to previous systemic chemotherapy. Overall, more than half (56%) of patients treated with Taxol experience an anticancer response, and the responses last an average of almost nine months. The majority of patients who responded (70%) did so after six weeks of treatment and four cycles of therapy. However, complete anticancer responses were observed in only four of the 54 patients who responded. Patients who responded to treatment also experienced a significant improvement in quality of life. It has not been determined whether Taxol may extend survival.
Taxotere has also been shown to produce partial anticancer responses in nearly half of patients with recurrent disease and produced stable disease in another one-third of patients. On average, patients survived more than two years without disease progression.
Early chemotherapy for flare of Kaposi's after initiation of HAART: Researchers have reported a worsening of Kaposi's sarcoma with the initiation of HAART. A flare-up of Kaposi's is associated with a fatal disorder of the immune system, called immune reconstitution inflammatory syndrome (IRIS), which may follow initiation of HAART. An IRIS-associated flare does not necessarily result in a poor prognosis. Even for those patients with a rapid and symptomatic onset, early systemic chemotherapy can effectively suppress an IRIS-associated flare. Close clinical supervision of patient initiating, changing, or resuming HAART may lead to earlier diagnosis of IRIS-associated flare, when it is most treatable.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.