Gastrointestinal stromal tumors (GISTs) are a type of tumor that occurs in the gastrointestinal tract, primarily in the stomach and small intestine. They arise from specialized cells called interstitial cells of Cajal, which are involved in regulating gut movement. GISTs can vary in size and may be benign or malignant. These tumors are often associated with mutations in the KIT gene, which plays a role in cell growth. Symptoms may include abdominal pain, nausea, and gastrointestinal bleeding. Diagnosis typically involves imaging studies and biopsy, while treatment often includes surgery and targeted therapies like imatinib.