Gastrointestinal-stromal tumors (GIST) are a rare form of cancer that typically occurs in the stomach but which may also be found in the small intestine and elsewhere in the gastrointestinal tract. They can develop in people of all ages but are significantly more common in those between 50 and 70 years of age. 

Possible symptoms of GIST include anemia, abdominal pain, nausea, vomiting, loss of appetite, loss of weight, problems swallowing, black stools, and a growth that can be felt in the abdomen. 

Treatment of GIST involves the use of prescription medication, chemotherapy, and surgery. Large or symptomatic GISTs are usually removed surgically. Protein kinase inhibitors, which work by stopping the growth of the cancer cells, are often prescribed to treat GIST.