What are the other Names for this Condition? (Also known as/Synonyms)

• Gastric Kaposi Sarcoma
• Kaposi's Sarcoma of Stomach
• KS of Stomach

What is Kaposi Sarcoma of Stomach? (Definition/Background Information)

• Kaposi sarcoma (KS) is a malignant tumor that is associated with human herpes viral infection (HHV8 infection). It generally manifests as a skin condition with lesions and purple red patches; mainly on the legs, hands, and face. But, it can also affect the lymph nodes, many vital organs, and mucous membranes lining the respiratory and digestive system leading to life-threatening situations
• Kaposi Sarcoma of Stomach is a rare high-grade malignancy that is seen in the stomach, mainly against a background of AIDS/HIV-infection. However, any individual with a weak or healthy immune system may be at risk for Kaposi Sarcoma of Stomach. The tumor is usually diagnosed in adults
• The presenting signs and symptoms of Kaposi Sarcoma of Stomach may include abdominal pain, unintended weight loss, and fatigue. KS can potentially affect the entire body and systemic signs and symptoms may be noted. Some tumors are small and show no symptoms; these are usually detected incidentally as submucosal nodules
• The treatment of Gastric Kaposi Sarcoma involves a combination of surgery, chemotherapy, and radiation therapy. Additionally, treatment of the underlying HIV infection or AIDS is undertaken
• With prompt diagnosis and adequate treatment, the prognosis of Kaposi Sarcoma of Stomach may be improved. Nevertheless, the prognosis depends upon various factors including on the presence of HIV/AIDS infection

Who gets Kaposi Sarcoma of Stomach? (Age and Sex Distribution)

• In general, Kaposi sarcoma may affect any individual of any age, gender, race, or ethnicity
• There are 4 main forms of Kaposi sarcoma; each specific form is known to affect a certain subset of individuals. Some forms of KS are endemic to certain geographical regions of the world (such as Africa or East Europe)
• Based on certain studies, about 40-50% AIDS/HIV-infected patients may show Kaposi Sarcoma of Stomach with other areas of the GI tract, such as the large intestine, being affected

What are the Risk Factors for Kaposi Sarcoma of Stomach? (Predisposing Factors)

The specific risk factors for Kaposi Sarcoma of Stomach include:

• HIV infection and AIDS; nearly 50% of the individuals with Kaposi sarcoma involving the GI tract is reported to have HIV infection/AIDS
• Some tumors are seen in transplant patients with weak immune system

In general, the risk factors for Kaposi sarcoma based on each specific type are described:

• Classic KS: Those belonging to the Mediterranean, East European, and Middle Eastern region, and Ashkenazi Jews have a high risk. Also, having a family history of the condition is a risk factor
• African endemic KS: Individuals belonging to the sub-Saharan regions of Africa are at risk. This includes the presence of conditions such as chronic malaria, parasitic infections, malnutrition, etc.
• Iatrogenic KS: Any medical condition necessitating treatment using immunosuppressive medications (such as an organ transplant), chemotherapy treatment, major illnesses, etc.
• AIDS-related KS: Any individual with AIDS or HIV infection

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Kaposi Sarcoma of Stomach? (Etiology)

Kaposi Sarcoma of Stomach may be caused by a complex interaction of the human herpes virus (HHV8), certain genetic factors, a weak immune system, and disease-conducive environmental conditions.

What are the Signs and Symptoms of Kaposi Sarcoma of Stomach?

The signs and symptoms of Kaposi Sarcoma of Stomach include:

• Initially, the small-sized tumors may be asymptomatic
• Most tumors occur as a mucosal or submucosal mass
• Tumors may be present anywhere in the stomach; other areas of the gastrointestinal tract may be involved (usually the colon/large intestine)
• Involvement of the skin is usually noted as skin lesions that bleed and ulcerate
• Large tumors can also bleed and ulcerate; this may result in blood in stool
• Involvement of lymph nodes may be noted, in advanced tumor cases
• Commonly observed symptoms for advanced cancer are abdominal pain and discomfort
• Large tumors may cause a pressure effect by compressing adjoining structures and organs

How is Kaposi Sarcoma of Stomach Diagnosed?

A diagnosis of Kaposi Sarcoma of Stomach is made by:

• Complete physical exam with evaluation of medical history
• Ultrasound scan of the stomach/abdomen: It is a non-invasive procedure that uses high frequency sound waves to produce real-time images
• Abdominal CT scan: It is a noninvasive procedure that provides more details of soft tissues, blood vessels, and internal organs
• Stool sample analysis
• Upper GI endoscopy: An endoscopic procedure is performed using an instrument called an endoscope, which consists of a thin tube and a camera. Using this technique, the radiologist can have a thorough examination of the insides of the gastrointestinal tract
• Chromoendoscopy can help detect small-sized tumors; small tumors can also be detected using narrow band imaging technique
• Endoscopic ultrasonography: During this procedure, fine needle aspiration biopsy (FNAB) can be performed on the affected area. This is good technique for tumor detection, including tumor invasion parameters, and whether nearby lymph nodes are affected
• Esophagogastroduodenoscopy (EGD): It is a procedure to check the linings of the esophagus, stomach, and duodenum. Through this procedure, biopsies may be performed at the same time. It is generally preferred for evaluating individuals with suspected stomach cancer
• Vascular angiographic studies of the tumor
• Exploratory laparoscopy (diagnostic laparoscopy) may be required, if gastrointestinal symptoms are present. In this procedure, the abdomen is examined using a minimally-invasive technique, and a tissue biopsy and tissue for culture obtained
• Whole body PET scans to determine how far the cancer has spread to other organ systems

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include:

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Core biopsy of the tumor
• Open biopsy of the tumor

Tissue biopsy of the tumor:

• A tissue biopsy of the nodule is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Note: A differential diagnosis may be used to eliminate other tumor types, before arriving at a definite diagnosis of Kaposi sarcoma.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Kaposi Sarcoma of Stomach?

The possible complications due to Kaposi Sarcoma of Stomach include:

• Vomiting, diarrhea, and weight loss may occur
• Ulceration and bleeding from the tumor; secondary bacterial or fungal skin infections may develop if the lesions ulcerate and bleed
• Perforation or rupture of the stomach
• Metastasis of KS to other vital body organs; the entire body could be severely affected leading to fatalities
• KS can recur, even after the full treatment course is completed
• Side effects from chemotherapy (such as toxicity) and radiation therapy
• Damage to the muscles, vital nerves, and blood vessels, during surgery
• Post-surgical wound infection

How is Kaposi Sarcoma of Stomach Treated?

There is no definitive cure for Kaposi Sarcoma of Stomach, since it is caused by a virus (HHV8). The signs and symptoms can only be controlled. The treatment depends upon the location and extent of spread of the tumors. A combination of procedures is used to treat KS; usually, surgery is the treatment of choice followed by chemotherapy.

• When the tumor is confined to the surface, then endoscopic mucosal/submucosal resection (or surgical removal via endoscopy) is undertaken
• Gastrectomy or surgery to remove part (or all) of the stomach, termed subtotal (partial) gastrectomy or total gastrectomy respectively
• When the tumor is at an inaccessible location, or is unsafe for surgical intervention, non-invasive procedures, such as chemotherapy and radiation therapy (using fast neutron-beam), may be considered
• Embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Palliative care is provided for advanced cancer stages
• Clinical trial therapies (especially for stage IV disease) including therapeutic drugs, radiation, stem cell transplantation, and monoclonal antibodies, either singly or in combination of various therapies
• The commonly used therapy called ‘highly-active antiretroviral therapy’ (HAART) has been shown to considerably improve the condition in AIDS-affected individuals
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Post-operative follow-up care with regular screening and check-ups are important, especially to monitor for any recurrences

Each form of Kaposi sarcoma responds to treatment in a different manner and is treated accordingly. The treatment also depends on the health of the patient and the individual’s specific response to treatment.

How can Kaposi Sarcoma of Stomach be Prevented?

While it may be difficult to prevent Kaposi Sarcoma of Stomach, some forms of KS may be prevented by considering the following factors:

• Adhering to safe sexual practices and avoiding multiple partners
• Controlling some of the modifiable risk factors, such as malaria, malnutrition, and recurrent parasitic treatment, through early diagnosis and treatment
• Testing organ donors for human herpes virus infection can be helpful
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations, are mandatory for those who have been diagnosed with the tumor
• Due to its high metastasizing potential and chances of recurrence, often several years of active follow-up and vigilance is recommended

What is the Prognosis of Kaposi Sarcoma of Stomach? (Outcomes/Resolutions)

• The prognosis of Kaposi Sarcoma of Stomach is improved, if the condition is diagnosed early, it is still in its mild form, and the individual does not have a weak immune system. Nevertheless, involvement of the internal organs in Kaposi sarcoma generally portrays a poor outcome
• The prognosis of KS of Stomach is guarded in individuals with HIV infection or AIDS; deaths due to AIDS complications are generally high
• The prognosis of stomach cancer, in general, depends upon a set of several factors that include: 
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Individuals with bulky disease have a poorer prognosis
  • Involvement of the lymph node can adversely affect the prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical resectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment of Stomach cancer: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
  • Progression of the condition makes the outcome worse
• An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment

Additional and Relevant Useful Information for Kaposi Sarcoma of Stomach:

The 4 different types of Kaposi sarcoma are known to affect 4 diverse (ethnic) groups of people; unlike other forms of cancer that affect different cells or organs, in the same individual. This trait of KS remains medically unexplained.