GIST, which stands for gastrointestinal stromal tumor, is a tumor that typically begins in the cells of the gastrointestinal (GI) tract wall. The tumor can be benign or malignant. Malignant GISTs may occur from the esophagus to the rectum (or near the GI tract), but most commonly occur in the stomach and small intestine.

Gastrointestinal stromal tumors are derived from particular cells in the GI tract known as interstitial cells of Cajal (ICCs). There are various types of ICCs:

  • Myenteric interstitial cells of Cajal (ICC-MY)
  • Intramuscular interstitial cells of Cajal (ICC-IM)

Signs and symptoms of a GIST tumor include:

  • Abdominal discomfort or pain
  • Changes in bowel habits
  • Blood in stool
  • Painless lump in the abdomen
  • Nausea or vomiting
  • Fatigue
  • Fever and night sweats
  • Trouble swallowing
  • Unexplained weight loss

Gastrointestinal stromal tumors that are small and not highly proliferative have a lower risk of recurrence and, therefore no further treatment is typically indicated. However, the risk of GIST returning after surgical resection is increased if the tumor is large, or if it originated somewhere in the body other than the gastrointestinal tract.