If you have been suffering from prolonged acidity heartburn unexplained weight loss and changes in bowel pattern chances are your doctor might want to go for a detailed investigation of your intestine. The next step would be to go for an endoscopy. However if your doctor suspects something really serious going for an endoscopy alone might not help. In the case of a tumour in the intestine an endoscopy of the upper intestine is done to study the nature of the growth. Typically a series of tests are done to ascertain its nature ultrasound followed by endoscopy imaging scans etc.