The tests and procedures you might undergo to diagnose a neuroendocrine tumor will depend on where your tumor is located in your body. In general, tests might include:
Physical exam: Your doctor may examine your body to better understand your signs and symptoms. He or she may feel for swollen lymph nodes or look for signs that a tumor is producing excess hormones.
Tests to look for excess hormones: Your doctor may recommend testing your blood or your urine for signs of excess hormones that are sometimes produced by neuroendocrine tumors.
Imaging tests: You might undergo imaging tests, such as ultrasound, CT and MRI, to create pictures of your tumor. For neuroendocrine tumors, pictures are sometimes created using positron emission tomography (PET) with a radioactive tracer that's injected into a vein.
Procedures to remove a sample of cells for testing (biopsy): To collect the cells, the doctor might insert a long, thin tube with a light and a camera on the end into your lungs (bronchoscopy), your esophagus (endoscopy) or your rectum (colonoscopy), depending on your situation. Sometimes, collecting a tissue sample requires surgery.
Courtesy: Mayo Clinic