A gastrointestinal stromal tumor, or GIST, is a tumor that grows from special nerve cells present in the walls of the digestive organs. These cells help move food through the body.
The interstitial cells of Cajal are a specialized type of cell found in the gastrointestinal (GI) tract. These cells help regulate food and liquid movement in the digestive system and coordinate smooth muscle contractions. Although it can occur at any age, GIST is most commonly diagnosed later in life, with a median age of diagnosis in the 60s.
GIST accounts for 0.1 to 3% of all gastrointestinal malignancies. It is mostly benign, with only about 30% of GISTs being malignant. It mainly occurs throughout the GI tract, with 60% of cases present in the stomach and 20% to 30% in the small intestine.
This soft tissue sarcoma rarely occurs outside the GI tract, but some start outside the digestive system in nearby areas such as:
- Omentum: This is a large adipose tissue layer that lines the abdominal cavity and covers the abdominal organs.
- Mesentery: This is a membrane that attaches the intestine to the wall around the stomach area and holds it in place.
- Peritoneum: This is a thin lining of tissue that covers the organs and lines the inside of the stomach.