A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal tract, primarily in the stomach and small intestine. These tumors arise from interstitial cells of Cajal or precursor cells, which are part of the nervous system in the digestive tract. GISTs can be benign or malignant and are often associated with mutations in the KIT gene. Symptoms of GISTs may include abdominal pain, nausea, and gastrointestinal bleeding. Diagnosis typically involves imaging studies, such as CT scans, and a biopsy to confirm the presence of the tumor. Treatment often includes surgical removal and targeted therapies, particularly for malignant cases.