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

• Appendiceal Gastrointestinal Stromal Tumor
• Appendiceal GIST
• GIST of Appendix

What is Gastrointestinal Stromal Tumor of Appendix? (Definition/Background Information)

• A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal tract. It can either be benign or malignant depending on various characteristics. Most tumors occur randomly, while some originate due to a family history of the condition
• The most common location of this tumor is the stomach or small intestine. The origin of the tumor is uncertain. Some researchers believe that these tumors originate from a special type of cells that are present in the gastrointestinal tract, called the interstitial cells of Cajal (ICCs)
• According to some reports, a GIST is the most commonly encountered mesenchymal tumor in the appendix. The appendix is a small blind pouch of the colon, located at the beginning of the large intestine/colon. However, based on the recorded number of cases, a Gastrointestinal Stromal Tumor of Appendix is very rare
• Gastrointestinal Stromal Tumor of Appendix may arise sporadically or in the presence of an associated genetic disorder, such as neurofibromatosis type 2, in a few cases. In a majority though, the involvement of KIT and PDGFRA genes are noted (for both sporadic and familial cases)
• Small-sized tumors are not known to cause any significant symptoms, but larger tumors may result in abdominal discomfort and blood in stool. Malignant tumors are known to metastasize to the colon, rectum, and other distant regions
• The standard treatment mode involves a surgical excision and removal of the entire tumor followed by chemotherapy. However, Gastrointestinal Stromal Tumor of Appendix outcome chiefly depends on the type of tumor - whether benign or malignant

Who gets Gastrointestinal Stromal Tumor of Appendix? (Age and Sex Distribution)

• Gastrointestinal Stromal Tumors of Appendix are very rare and only about 15 cases have been reported. Only 0.1% of all gastrointestinal tract GISTs form in the appendix
• GIST of Appendix is mostly observed in older adults (age range 56-78 years; average age is 67 years)
• Both males and females are affected, but a male predominance is noted (male-female ratio is 7:2)
• No racial or ethnic predilection is observed

What are the Risk Factors for Gastrointestinal Stromal Tumor of Appendix? (Predisposing Factors)

• Currently, no definitive risk factors for Gastrointestinal Stromal Tumor of Appendix are known, when the tumors occur sporadically (in a vast majority of the cases)
• However, in some rare cases, an association of the tumor with certain genetic disorders, such as neurofibromatosis type 2 (NF2), is noted

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 Gastrointestinal Stromal Tumor of Appendix? (Etiology)

The cause of Gastrointestinal Stromal Tumors of Appendix may be due to genetic mutations. In general, for GIST tumors:

• Mutations in two specific genes account for a majority of the cases. Mutation in these genes, result in an uncontrolled growth of cells, leading to tumor formation
• It is estimated that 80% of such tumors are caused by a mutation in the KIT gene; around 10% of diagnosed cases, caused by a mutation in the PDGFRA gene. The reminder of the tumors occurs, due to mutation in certain other genes

There are two types of gastrointestinal stromal tumors (GISTs): Sporadic tumors and familial tumors

• Both, familial and sporadic tumors are caused by mutations in the KIT and PDGFRA genes. These genes are responsible for making proteins that are involved in cell growth and cell death. In a minority of the cases, the mutations are inherited from parents and in such cases, are called familial GIST
• In familial GIST, mutations are inherited in an autosomal dominant pattern, which means that only one copy of the mutated gene in each cell is enough to increase an individual’s chance of developing gastrointestinal stromal tumors
• In sporadic cases of GIST, there is usually a single tumor, whereas in familial type of GISTs, multiple tumors may occur

What are the Signs and Symptoms of Gastrointestinal Stromal Tumor of Appendix?

In a majority of individuals, Gastrointestinal Stromal Tumor of Appendix does not cause any significant symptoms. They may be detected incidentally during imaging studies that are performed for other health condition.

In some individuals, the following signs and symptoms of GIST of Appendix may be present that include:

• Symptoms that are similar to acute appendicitis such as:
  • Abdominal pain that first originates around the umbilicus and then gradually moves towards a point on the right lower quadrant of the abdomen, called the McBurney’s point
  • Sometimes, the pain can occur anywhere in the upper or lower abdomen, back, or rectum
  • Nausea and vomiting
  • In some, fever, shivering, and chills may be noted
  • Loss of appetite
  • Constipation or diarrhea
  • Occasionally, painful urination and severe cramps can occur
• Presence of an abdominal mass with abdominal tenderness
• Swollen abdomen
• Tumors are seen at the tip of the appendix or middle portion of the appendix
• The tumor averages between 3 to 4 cm in size, although sizes up to 20 cm have been recorded
• Bleeding from the tumor may result in blood in stool
• Most tumors are benign, while some are rarely malignant

Some individuals may have associated carcinomas at other GI regions.

How is Gastrointestinal Stromal Tumor of the Colon Diagnosed?

A diagnosis of Gastrointestinal Stromal Tumor of Appendix would involve the following tests and exams:

• Physical exam and evaluation of medical history
• Complete blood count (CBC)
• Basic metabolic panel
• X-ray of abdomen
• Ultrasound or CT scan of abdomen
• Screening colonoscopy: A colonoscopy is a test that allows the physician to look at the inner lining of the colon and rectum. A typical colonoscopy involves using a thin, flexible tube (called a colonoscope), with an attached video camera, to view the colon and rectum

A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination.

• A pathologist examines the biopsy under a microscope. If it is indeed a polyp, a distinct appearance is noted by the pathologist. 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

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 Gastrointestinal Stromal Tumor of Appendix?

Gastrointestinal Stromal Tumors of Appendix may give rise to the following complications:

• Rupture/perforation of the appendix
• Acute peritonitis secondary to rupture/perforation of the appendix (spread of infection to areas outside of appendix)
• Abscess formation in the appendix
• Tumor infiltration to abdominal and pelvic organs, such as colon, rectum, and urinary bladder, from malignant tumors (which are occasionally observed)
• Metastasis to local and regional sites; spread of tumor to the lymph nodes
• Recurrence of the tumor after surgery is generally rare
• Post-operative complications: Infection of the surgical wound after operating upon the tumor

How is Gastrointestinal Stromal Tumor of Appendix Treated?

The treatment measures for Gastrointestinal Stromal Tumor of Appendix may include the following.

• A complete surgical resection of the tumor via the following procedures:
  • Open appendectomy: It involves making a deep incision on the lower abdomen and removing the appendix from the surrounding abdominal organs
  • In laparoscopic approach, a surgeon makes 3 or 4 small incisions for insertion of the camera and the laparoscopic instruments and the appendix is cut and removed
  • Hemicolectomy, if necessary, which is the partial removal of the affected portion of the colon, along-with the tumor
• Non-surgical intervention includes chemotherapy and/or radiotherapy - these modalities are generally used to shrink the tumor, if possible, before an invasive surgical procedure is planned and performed
• Arterial or chemo-embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Post-operative care is important: A minimum activity level is to be ensured, until the surgical wound heals

Regular observation and periodic checkups to monitor the condition is recommended following treatment.

How can Gastrointestinal Stromal Tumor of Appendix be Prevented?

Currently, there are no known preventive methods for Gastrointestinal Stromal Tumor of Appendix. However, if it is associated with a genetic disorder, the following points may be considered:

• Genetic counseling and testing: If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Regular health check-ups might help those individuals with a history of the condition in the immediate family and help diagnose the tumor early

Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory. Often several years of active vigilance are crucial and necessary.

What is the Prognosis of Gastrointestinal Stromal Tumor of Appendix? (Outcomes/Resolutions)

The prognosis for individuals with Gastrointestinal Stromal Tumor (GIST) of Appendix depends on whether the tumor is benign or malignant.

• The prognosis is generally excellent for benign tumors following their surgical excision
• However, the prognosis of malignant GIST tumors may depend on a set of 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
  • Overall health of the individual
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Individuals with bulky disease may have a poorer 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: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment; good response to treatment (surgery and/or chemotherapy/radiation therapy)
  • Progression of the condition makes the outcome worse
• Generally, the prognosis of malignant GIST is variable. Some are known to metastasize early and can lead to death in a few years; while others may take several years to spread to other sites. In rare cases, when malignant tumors are seen in the mediastinal region, they are reported to show a much better prognosis
• 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 Gastrointestinal Stromal Tumor of Appendix:

The following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/