Gastrointestinal stromal tumors (GISTs) are soft-tissue sarcomas that can be located in any part of the digestive system. Their most common sites are the stomach and small intestine.
Small GISTs may cause no symptoms, and they may grow so slowly that they have no serious effects. People with larger GISTs usually seek medical attention when they vomit blood or pass blood in their stool due to rapid bleeding from the tumor.
Other possible GIST symptoms include:
- Anemia, caused by a slow-bleeding tumor
- Abdominal pain
- A growth you can feel in your abdomen
- Loss of appetite
- Weight loss
- Difficulty swallowing
GISTs can develop in people of all ages, but they are most common between age 50 and 70, and they almost never occur before age 40. In rare cases, an inherited genetic change (mutation) causes GISTs.