Diagnosis
If a person has any symptoms of a functioning islet cell tumor, a doctor should conduct a physical examination and take a full medical history. The doctor may also ask about the patient's family history and any known inherited genetic diseases that may increase the risk of developing the disease. If the doctor suspects an islet cell tumor, he or she may recommend one or more of the following diagnostic procedures:
Laboratory Tests
The doctor may recommend blood tests to measure the levels of different hormones and substances that may be produced by an islet cell tumor, such as chromogranin A, serotonin, insulin, gastrin, VIP, glucagon, and 5HIAA. The doctor will take a blood sample and send it to a laboratory for further testing. The doctor may also take a urine or stool sample, or a sample of acid from the stomach or small intestine.
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CT Scan
A computerized tomography (CT) scan creates detailed images of the internal organs. The doctor may recommend a CT scan to determine the presence, size, and location of the tumor. In patients who are not allergic, IV contrast is usually administered, as islet cell tumors often appear quite different from other pancreatic tumors.
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MRI scan
An MRI uses radio waves and a strong magnet to create clear and detailed images of body parts. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show “slices” of the body. The doctor may use an MRI to identify the exact location of an islet cell tumor. Gadolinium, an MRI contrast agent, is usually administered to obtain the best results. This test may be especially useful in determining if the tumor has spread to the liver.
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Endoscopic Ultrasound (EUS)
An endoscope is a thin tube with a camera and a light on the end. In this procedure, the doctor inserts an endoscope with an ultrasound transducer attached at the end. The transducer bounces sound waves off of internal organs in order to create a picture of the pancreas, as well as nearby organs and lymph nodes.
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Somatostatin receptor scintigraphy
In this procedure, a radioactive form of octeotride, which is a synthetic form of somatostatin, is injected into the patient's body. This substance travels through the body and is absorbed by the tumor. The doctor then uses a special camera to detect the radioactivity and determine the location of the tumor. Doctors may use this procedure to find small islet cell tumors or identify sites where the tumor has spread.
Biopsy
Your doctor may decide to remove a small sample of tissue from the pancreas or another site such as the liver in order to physically look at the tumor cells under a microscope. This procedure is known as a biopsy. The sample can be obtained with a needle guided by CT scan or endoscopic ultrasound.
