Because GISTs do not interfere directly with the workings of an organ, they often grow for some time without producing any symptoms. Even when they do produce symptoms, these are very varied, and all of them can be caused by other things. It is the presence of one or more of these symptoms, which cannot be explained in any other way, which should lead to a possible diagnosis of GIST. If a tumour is found which may be a GIST, current opinion is that it is probably best to remove the tumour, if possible, without doing a biopsy. Many GISTs are only firmly diagnosed after surgery. They are sometimes found when the patient is being operated on for something else. If it is not possible to remove the tumour, then a biopsy may be done endoscopically. (Using an instrument passed into the stomach or intestines through the mouth.) A firm diagnosis of GIST can only be made by a pathologist looking at the tumour tissue with a microscope.

POSSIBLE SYMPTOMS

• Discomfort or pain in the stomach or intestines
  
• Indigestion
  
• Nausea
  
• Swelling
  
• Bleeding from the stomach or intestines
  
• Weight gain
  
• Weight loss
  
• Fever
  
• Night sweats