Introduction About GIST in Special Gastric GIST A gastrointestinal stromal tumor (GIST) is a soft tissue sarcoma which grows as loose tissue and spreads across the gastrointestinal (GI) track. The tumor is not common, occuring in less than 1% of GI tumors, although it is the most common mesenchymal neoplasm to affect the GI tract. 1,2 Sarcoma can occur anywhere along the GI, but it is common in the stomach and small intestine. The tumor varies in characteristics depending on the location, size, and cell division. Tumor size can vary between 4 mm and 35 cm. 1 The characteristics determine whether the GIST expands to other areas of the body. GISTs occur in the interstitial cells of Cajal (ICC), also called the "pacemakers". 3,4 The cells belong to the autonomic nervous system, which is responsible for regulating processes of the body like food digestion. ICCs signal the GI to contract and relax the muscles to allow food and other liquids to flow. 5 Although there is not much information about the risk factors of GIST, it is known to affect people between the ages of 40 and 80 years. 6 Also, there is a rare uninherited risk factor, a gene mutation, which increases the chance of a person developing GIST. Another risk factor is the primary familial GIST syndrome, an inherited condition. 1 The syndrome can lead to the development of GIST at an earlier age than the expected 40 years and in more than one form. Primary familial GIST syndrome originates from KIT, an abnormal gene that a child inherits from parents. 7 The abnormal gene is found in all cells of those people who inherit it and in cancer cells for those with sporadic GIST. The syndrome can also