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Gastrointestinal Stromal Tumor (GIST)

A gastrointestinal stromal tumor, or GIST, is a type of submucosal nodule that most commonly occurs in the stomach, but can also be found in the small intestine. GISTs are often benign, but it's estimated that between 10 and 30 percent of GISTs are cancerous. Cancerous GISTs are typically larger than benign GISTs, and have an irregular shape. A biopsy procedure called endoscopic ultrasound-guided fine needle aspiration, or EUS-FNA, may be used to determine whether a GIST is benign or cancerous.

Small tumors may cause no symptoms, but larger GISTs may cause pain or swelling in the abdomen, nausea, vomiting, loss of appetite, or weight loss. In some cases, tumors may cause bleeding. Bleeding into the upper intestinal tract can result in black and tarry stools, and bleeding into the throat or stomach can cause vomiting of blood.

When a person has only one tumor, it's called a sporadic GIST. People with a family history of GISTs often have multiple tumors.

Very small GISTs that do not cause any symptoms may be treated with a "wait-and-see" approach. This means keeping an eye on the tumor with endoscopy or endoscopic ultrasound once or twice a year. If the tumor isn't changing or growing, no further treatment may be needed.

For most GISTs, however, it's necessary to remove the tumor. Smaller GISTs may be surgically removed. Larger GISTs may require targeted drug treatment to shrink the tumor before surgery can be done. Depending on the size of the GIST, it may take several different targeted drug treatments to shrink the tumor enough to attempt surgery.