Many patients (mostly those with smaller tumors) have no symptoms.
Larger tumors may cause symptoms that are generally related to the increased mass being accommodated in the abdominal cavity, and such symptoms would not necessarily be different from those other types of tumors.
Symptoms include digestive discomfort, sensations of abdominal fullness, or abdominal pain.
Larger tumors may be detectable as a mass when feeling the abdomen, or as a visible enlargement of the abdomen.
Some patients experience vomiting or diarrhea or intestinal obstruction may occur in some patients.
Sometimes GISTs perforate the stomach or gut lining and bleed into the GI tract, resulting in black or tarry stools, or occasionally in vomiting of blood. Anemia (Low Haemoglobin) may result from chronic bleeding, leading to fatigue. Sometimes anemia may cause the patient’s heart to race (tachycardia). The patient may notice weight loss.
Very rarely a GIST may rupture, making its presence known with a medical emergency.
Though such symptoms are possible, most of them are rather indistinct and merely related to the additional mass that is present in the abdomen. Therefore, many GISTs are found incidentally through medical imaging for other purposes or through surgery for other conditions.