gastrointestinal stromal tumors
[gas-tro-in-TEST-uh-nul stro-muhl too-mers]
also called GISTs. Tumors that grow from special cells on the gastrointestinal wall known as the interstitial cells of Cajal. Most GISTs start in the stomach or small intestine. These tumors may or may not be cancer. GIST cancers are very different from other more common types of GI tract cancers in treatment and outlook. See also gastrointestinal tract.