Diagnosis of adenocarcinoma begins with a medical history and physical exam. An upper GI X-ray study will usually show a mass pressing on the intestine. A small tube called an endoscope can be passed into the intestine to help view the mass. The tube has a light and a camera on the end of it. This allows the doctor to see the inside of the intestine.
A small piece of the mass is removed and examined. This small sample is called a biopsy. This biopsy helps to confirm that the mass is cancerous.