Kaposi's sarcoma
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Kaposi's sarcoma (KS) is a type of
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
that can form masses in the
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
, in
lymph nodes A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that inclu ...
, in the mouth, or in other
organs In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
. The skin lesions are usually painless,
purple Purple is any of a variety of colors with hue between red and blue. In the RGB color model used in computer and television screens, purples are produced by mixing red and blue light. In the RYB color model historically used by painters, ...
and may be flat or raised. Lesions can occur singly, multiply in a limited area, or may be widespread. Depending on the sub-type of disease and level of immune suppression, KS may worsen either gradually or quickly. Except for Classical KS where there is generally no immune suppression, KS is caused by a combination of
immune suppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...
(such as due to
HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...
) and infection by
Human herpesvirus 8 Kaposi's sarcoma-associated herpesvirus (KSHV) is the ninth known human herpesvirus; its formal name according to the International Committee on Taxonomy of Viruses (ICTV) is ''Human gammaherpesvirus 8'', or HHV-8 in short. Like other herpesviru ...
(HHV8 – also called KS-associated herpesvirus (KSHV)). Four sub-types are described: classic, endemic, immunosuppression therapy-related (also called iatrogenic), and epidemic (also called AIDS-related). Classic KS tends to affect older men in regions where KSHV is highly prevalent (Mediterranean, Eastern Europe, Middle East), is usually slow-growing, and most often affects only the legs. Endemic KS is most common in Sub-Saharan Africa and is more aggressive in children, while older adults present similarly to classic KS. Immunosuppression therapy-related KS generally occurs in people following
organ transplantation Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organ ...
and mostly affects the skin. Epidemic KS occurs in people with
AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual m ...
and many parts of the body can be affected. KS is diagnosed by
tissue biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disea ...
, while the extent of disease may be determined by medical imaging. Treatment is based on the sub-type, whether the condition is localized or widespread, and the person's immune function. Localized skin lesions may be treated by surgery, injections of
chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
into the lesion, or
radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radi ...
. Widespread disease may be treated with chemotherapy or
biologic therapy A biopharmaceutical, also known as a biological medical product, or biologic, is any pharmaceutical drug product manufactured in, extracted from, or semisynthesized from biological sources. Different from totally synthesized pharmaceuticals, t ...
. In those with HIV/AIDS,
highly active antiretroviral therapy The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs as a strategy to control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life-cycle. The use of multip ...
(HAART) prevents and often treats KS. In certain cases the addition of chemotherapy may be required. With widespread disease, death may occur. The condition is relatively common in people with HIV/AIDS and following organ transplant. Over 35% of people with AIDS may be affected. KS was first described by
Moritz Kaposi Moritz Kaposi ( hu, Kaposi Mór, ; 23 October 1837 in Kaposvár, Hungary – 6 March 1902 in Vienna, Austria-Hungary) was a Hungarian physician and dermatologist who discovered the skin tumor that received his name (Kaposi's sarcoma). Biography ...
in 1872. It became more widely known as one of the AIDS-defining illnesses in the 1980s. KSHV was discovered as a causative agent in 1994.


Signs and symptoms

KS
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...
s are nodules or blotches that may be red, purple, brown, or black, and are usually
papular A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this ...
. They are typically found on the skin, but spread elsewhere is common, especially the mouth,
gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...
and respiratory tract. Growth can range from very slow to explosively fast, and is associated with significant mortality and
morbidity A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
. The lesions are painless, but become cosmetically disfiguring or interruptive to organs.


Skin

Commonly affected areas include the
lower limbs The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb e ...
, back, face, mouth, and
genitalia A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...
. The lesions are usually as described above, but may occasionally be
plaque Plaque may refer to: Commemorations or awards * Commemorative plaque, a plate or tablet fixed to a wall to mark an event, person, etc. * Memorial Plaque (medallion), issued to next-of-kin of dead British military personnel after World War I * Pl ...
-like (often on the soles of the feet) or even involved in
skin breakdown Pressure ulcers, also known as pressure sores, bed sores or pressure injuries, are localised damage to the skin and/or underlying tissue that usually occur over a bony prominence as a result of usually long-term pressure, or pressure in combi ...
with resulting
fungating lesion A fungating lesion is a skin lesion that fungates, that is, becomes like a fungus in its appearance or growth rate. It is marked by ulcerations (breaks on the skin or surface of an organ) and necrosis (death of living tissue) and usually presents ...
s. Associated swelling may be from either local
inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
or
lymphoedema Lymphedema, also known as lymphoedema and lymphatic edema, is a condition of localized swelling caused by a compromised lymphatic system. The lymphatic system functions as a critical portion of the body's immune system and returns interstitial f ...
(obstruction of local
lymphatic vessels The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessel ...
by the lesion). Skin lesions may be quite disfiguring for the patient, and a cause of much psychosocial pathology.


Mouth

The mouth is involved in about 30% of cases, and is the initial site in 15% of AIDS-related KS. In the mouth, the
hard palate The hard palate is a thin horizontal bony plate made up of two bones of the facial skeleton, located in the roof of the mouth. The bones are the palatine process of the maxilla and the horizontal plate of palatine bone. The hard palate spans t ...
is most frequently affected, followed by the
gums The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health. Structure The gums are part of the soft tissue lin ...
. Lesions in the mouth may be easily damaged by chewing and bleed or develop secondary infection, and even interfere with eating or speaking.


Gastrointestinal tract

Involvement can be common in those with transplant-related or AIDS-related KS, and it may occur in the absence of skin involvement. The gastrointestinal lesions may be silent or cause weight loss, pain, nausea/vomiting,
diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
, bleeding (either vomiting blood or passing it with bowel movements),
malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
, or
intestinal obstruction Bowel obstruction, also known as intestinal obstruction, is a mechanical or functional obstruction of the intestines which prevents the normal movement of the products of digestion. Either the small bowel or large bowel may be affected. Signs a ...
.


Respiratory tract

Involvement of the airway can present with shortness of breath,
fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
,
cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...
, coughing up blood or chest pain, or as an incidental finding on
chest x-ray A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in med ...
. The diagnosis is usually confirmed by
bronchoscopy Bronchoscopy is an endoscopic technique of visualizing the inside of the airways for diagnostic and therapeutic purposes. An instrument (bronchoscope) is inserted into the airways, usually through the nose or mouth, or occasionally through a trac ...
, when the lesions are directly seen and often biopsied. Kaposi's sarcoma of the lung has a poor prognosis.


Cause

Kaposi's sarcoma-associated herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) is the ninth known human herpesvirus; its formal name according to the International Committee on Taxonomy of Viruses (ICTV) is ''Human gammaherpesvirus 8'', or HHV-8 in short. Like other herpesvir ...
(KSHV), also called HHV-8, is present in almost 100% of Kaposi sarcoma lesions, whether HIV-related, classic, endemic, or
iatrogenic Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence. "Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 2 ...
. KSHV encodes
oncogenes An oncogene is a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels.
,
microRNAs MicroRNA (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. Found in plants, animals and some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miR ...
and
circular RNA Circular RNA (or circRNA) is a type of single-stranded RNA which, unlike linear RNA, forms a covalently closed continuous loop. In circular RNA, the 3' and 5' ends normally present in an RNA molecule have been joined together. This feature confe ...
s that promote cancer cell proliferation and escape from the immune system.


Transmission

In Europe and North America, KSHV is transmitted through saliva. Thus, kissing is a risk factor for transmission. Higher rates of transmission among gay and bisexual men have been attributed to "deep kissing" sexual partners with KSHV. Another alternative theory suggests that use of saliva as a sexual lubricant might be a major mode for transmission. Prudent advice is to use commercial lubricants when needed and avoid deep kissing with partners with KSHV infection or whose status is unknown. KSHV is also transmissible via organ transplantation and blood transfusion. Testing for the virus before these procedures is likely to effectively limit iatrogenic transmission.


Pathology

Despite its name, in general it is not considered a true
sarcoma A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal ( connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sar ...
, which is a tumor arising from mesenchymal tissue. The
histogenesis Histogenesis is the formation of different tissues from undifferentiated cells. These cells are constituents of three primary germ layers, the endoderm, mesoderm, and ectoderm. The science of the microscopic structures of the tissues formed wi ...
of KS remains controversial. KS may arise as a
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
of
lymphatic Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to ...
endothelium The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vesse ...
and forms vascular channels that fill with blood cells, giving the tumor its characteristic bruise-like appearance. KSHV proteins are uniformly detected in KS cancer cells. KS lesions contain tumor cells with a characteristic abnormal elongated shape, called ''spindle cells''. The most typical feature of Kaposi sarcoma is the presence of spindle cells forming slits containing red blood cells. Mitotic activity is only moderate and pleomorphism is usually absent. The tumor is highly
vascular The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...
, containing abnormally dense and irregular blood vessels, which leak red blood cells into the surrounding tissue and give the tumor its dark color.
Inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
around the tumor may produce swelling and pain. Variously sized PAS positive hyaline bodies are often seen in the cytoplasm or sometimes extracellularly. The spindle cells of Kaposi sarcoma differentiate toward
endothelial cells The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
, probably of lymph vessel rather than blood vessel origin. The consistent
immunoreactivity An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoassay ...
for
podoplanin Podoplanin is a protein that in humans is encoded by the ''PDPN'' gene. Structure and function Podoplanin is a mucin-type protein with a mass of 36- to 43-kDa. It is relatively well conserved between species, with homologues in humans, mice, rat ...
supports the lymphatic nature of the lesion. File:Micrograph of promontory sign of kaposi's sarcoma.jpg, Micrograph of promontory sign in Kaposi's sarcoma in patch stage. Dilated irregular vascular channels surround a pre-existing vessel. File:Micrograph of plaque stage of Kaposi's sarcoma.jpg, Micrograph of plaque stage, with bizarre vessels dissecting the upper dermis. There is erythrocyte extravasation and hemosiderin pigmentation. File:Micrograph of tumor stage of Kaposi's sarcoma.jpg, Micrograph of tumor stage. Well-circumscribed spindle-cell tumor. Erythrocytes lie within poorly defined slit-like vascular spaces.


Diagnosis

Although KS may be suspected from the appearance of lesions and the patient's risk factors, a definite diagnosis can be made only by
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...
and microscopic examination. Detection of the KSHV protein
LANA Lana may refer to: *Lana (given name) *Francesco Lana de Terzi (1631–1687), Italian Jesuit priest and scientist *Lana (wrestler), professional wrestler and pro wrestling manager *''Wild Energy. Lana'', a 2006 Ukrainian fantasy novel Sciences *L ...
in tumor cells confirms the diagnosis. In differential diagnosis, arteriovenous malformations,
pyogenic granuloma A pyogenic granuloma or lobular capillary hemangioma is a vascular tumor that occurs on both mucosa and skin, and appears as an overgrowth of tissue due to irritation, physical trauma, or hormonal factors. It is often found to involve the gums ...
and other vascular proliferations can be microscopically confused with KS.


Differential diagnosis of Kaposi's sarcoma

Source: # Naevus # Histiocytoma # Cryptococcosis # Histoplasmosis # Leishmaniasis # Pneumocystis lesions # Dermatophytosis # Angioma # Bacillary angiomatosis # Pyogenic granuloma # Melanoma


Classification

HHV-8 is responsible for all varieties of KS. Since
Moritz Kaposi Moritz Kaposi ( hu, Kaposi Mór, ; 23 October 1837 in Kaposvár, Hungary – 6 March 1902 in Vienna, Austria-Hungary) was a Hungarian physician and dermatologist who discovered the skin tumor that received his name (Kaposi's sarcoma). Biography ...
first described the cancer, the disease has been reported in five separate clinical settings, with different presentations, epidemiology, and prognoses. All of the 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.. 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 The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...
region,
Arab countries The Arab world ( ar, اَلْعَالَمُ الْعَرَبِيُّ '), formally the Arab homeland ( '), also known as the Arab nation ( '), the Arabsphere, or the Arab states, refers to a vast group of countries, mainly located in Western As ...
, or of
Eastern European Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russia, whi ...
descent.
Israeli Jews Israeli Jews or Jewish Israelis ( he, יהודים ישראלים, translit=Yehudim Yisraelim) are Israeli citizens and nationals who are Jewish through either their Jewish ethnicity and/or their adherence to Judaism. The term also include ...
have a higher rate of KSHV/HHV-8 infection than
European peoples Europeans are the focus of European ethnology, the field of anthropology related to the various ethnic groups that reside in the states of Europe. Groups may be defined by common genetic ancestry, common language, or both. Pan and Pfeil (2004) ...
. * ''Endemic KS'', which has two types. Although this may be present worldwide, it has been originally described later in young
African peoples African or Africans may refer to: * Anything from or pertaining to the continent of Africa: ** People who are native to Africa, descendants of natives of Africa, or individuals who trace their ancestry to indigenous inhabitants of Africa *** Ethn ...
, mainly those from
sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...
. This variant is not related to
HIV infection Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ma ...
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. ** ''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. * ''Immunosuppression-associated Kaposi sarcoma'' had been described, but only rarely until the advent of
calcineurin inhibitors Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified into ...
(such as
ciclosporin Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease ...
es, which are inhibitors of
T-cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...
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
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...
s that begin as one or several red to purple-red
macule A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this s ...
s, rapidly progressing to
papule A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...
s, nodules, and
plaque Plaque may refer to: Commemorations or awards * Commemorative plaque, a plate or tablet fixed to a wall to mark an event, person, etc. * Memorial Plaque (medallion), issued to next-of-kin of dead British military personnel after World War I * Pl ...
s, with a predilection for the head, back, neck, trunk, and
mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
s. In more advanced cases, lesions can be found in the stomach and intestines, the lymph nodes, and the lungs. Compared to other forms of KS, KS-AIDS stimulated more interest in KS research, as it was one of the first illnesses associated with
AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual m ...
and first described in 1981. This form of KS 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.


Prevention

Blood tests to detect antibodies against KSHV have been developed and can be used to determine whether a person is at risk for transmitting the infection to their sexual partner, or whether an organ is infected before transplantation. However, these tests are not available except as research tools, and, thus, there is little screening for persons at risk for becoming infected with KSHV, such as people following a transplant.


Treatment

Kaposi sarcoma is not curable, but it can often be treatable for many years. In KS associated with immunodeficiency or immunosuppression, treating the cause of the immune system dysfunction can slow or stop the progression of KS. In 40% or more of patients with AIDS-associated Kaposi sarcoma, the Kaposi lesions will shrink upon first starting
highly active antiretroviral therapy The management of HIV/AIDS normally includes the use of multiple antiretroviral drugs as a strategy to control HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life-cycle. The use of multip ...
(HAART). Therefore, HAART is considered the cornerstone of therapy in AIDS-associated Kaposi sarcoma. However, in a certain percentage of such people, Kaposi sarcoma may recur after many years on HAART, especially if HIV is not completely suppressed. People with a few local lesions can often be treated with local measures such as radiation therapy or
cryosurgery Cryosurgery is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. The term comes from the Greek words cryo (κρύο) ("icy cold") and surgery (''cheirourgiki'' – χ ...
. Weak evidence suggests that antiretroviral therapy in combination with
chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
is more effective than either of those two therapies individually. Limited basic and clinical evidence suggest that topical
beta-blocker Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack (secondary prevention). They are al ...
s, such as
timolol Timolol is a beta blocker medication used either by mouth or as eye drops. As eye drops it is used to treat increased pressure inside the eye such as in ocular hypertension and glaucoma. By mouth it is used for high blood pressure, chest pa ...
, may induce regression of localized lesions in classic as well as HIV-associated Kaposi sarcoma. In general, surgery is not recommended, as Kaposi sarcoma can appear in wound edges. In general, more widespread disease, or disease affecting internal organs, is treated with systemic therapy with
interferon Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten the ...
alpha, liposomal
anthracycline Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from ''Streptomyces'' bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder canc ...
s (such as liposomal
doxorubicin Doxorubicin, sold under the brand name Adriamycin among others, is a chemotherapy medication used to treat cancer. This includes breast cancer, bladder cancer, Kaposi's sarcoma, lymphoma, and acute lymphocytic leukemia. It is often used toge ...
or
daunorubicin Daunorubicin, also known as daunomycin, is a chemotherapy medication used to treat cancer. Specifically it is used for acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), and Kaposi's sarcoma. I ...
),
thalidomide Thalidomide, sold under the brand names Contergan and Thalomid among others, is a medication used to treat a number of cancers (including multiple myeloma), graft-versus-host disease, and a number of skin conditions including complications o ...
, or
paclitaxel Paclitaxel (PTX), sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical canc ...
.
Alitretinoin Alitretinoin, or 9-cis-retinoic acid, is a form of vitamin A. It is also used in medicine as an antineoplastic (anti-cancer) agent developed by Ligand Pharmaceuticals. It is a first generation retinoid. Ligand gained Food and Drug Administration ...
, applied to the lesion, may be used when the lesion is not getting better with standard treatment of HIV/AIDS and chemotherapy or radiation therapy cannot be used.


Epidemiology

With the decrease in the death rate among people with HIV/AIDS receiving new treatments in the 1990s, the rates and severity of epidemic KS also decreased. However, the number of people living with HIV/AIDS is increasing in the United States, and it is possible that the number of people with AIDS-associated Kaposi sarcoma will again rise as these people live longer with HIV infection.


Society

Because of their highly visible nature, external lesions are sometimes the presenting symptom of AIDS. Kaposi sarcoma entered the awareness of the general public with the release of the film ''
Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...
'', in which the main character was fired after his employers found out he was HIV-positive due to visible lesions. By the time KS lesions appear, likely, the immune system has already been severely weakened. It has been reported that only 6% of men who have sex with men are aware that KS is caused by a virus different from HIV. Thus, there is little community effort to prevent KSHV infection. Likewise, no systematic screening of organ donations is in place. In people with AIDS, Kaposi sarcoma is considered an
opportunistic infection An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...
, a disease that can gain a foothold in the body because the
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
has been weakened. With the rise of
HIV/AIDS in Africa HIV/AIDS originated in Africa in the early 20th century and is a major public health concern and cause of death in many African countries. AIDS rates vary significantly between countries, though the majority of cases are concentrated in Souther ...
, where KSHV is widespread, KS has become the most frequently reported cancer in some countries.


References


External links


Kaposi sarcoma photo library at Dermnet
{{DEFAULTSORT:Kaposi sarcoma HIV/AIDS Virus-related cutaneous conditions Connective and soft tissue neoplasms Vascular neoplasia Rare cancers Wikipedia medicine articles ready to translate