Key Points for This Section

Islet cell tumors are abnormal cells that form in the tissues of the pancreas. Islet cell tumors may or may not cause symptoms. There are different kinds of functional islet cell tumors. Having certain syndromes can increase the risk of developing islet cell tumors. Different types of islet cell tumors have different signs and symptoms. Lab tests and imaging tests are used to detect (find) and diagnose islet cell tumors. Other kinds of lab tests are used to check for the different types of islet cell tumors. Certain factors affect prognosis (chance of recovery) and treatment options.

Islet cell tumors are abnormal cells that form in the tissues of the pancreas.

The pancreas is a gland about 6 inches long that is shaped like a thin pear lying on its side. The wider end of the pancreas is called the head, the middle section is called the body, and the narrow end is called the tail. The pancreas lies behind the stomach and in front of the spine.

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Anatomy of the pancreas. The pancreas has three areas: head, body, and tail. It is found in the abdomen near the stomach, intestines, and other organs.

There are two kinds of cells in the pancreas:

• Endocrine pancreas cells make several kinds of hormones (chemicals that control the actions of certain cells or organs in the body), such as insulin to control blood sugar. They cluster together in many small groups (islets) throughout the pancreas. Endocrine pancreas cells are also called islet cells or islets of Langerhans. Malignant islet cell tumors are a rare type of pancreatic cancer.
• Exocrine pancreas cells make enzymes that are released into the small intestine to help the body digest food. Most of the pancreas is made of ducts with small sacs at the end of the ducts, which are lined with exocrine cells.

An islet cell tumor may also be called a pancreatic endocrine tumor (PET), pancreatic neuroendocrine tumor, islet cell carcinoma, or pancreatic carcinoid.

This summary discusses islet cell tumors of the endocrine pancreas. See the PDQ summary on Pancreatic Cancer Treatment ¹ for information on exocrine pancreatic cancer.

Islet cell tumors may or may not cause symptoms.

Islet cells make and release hormones into the blood. Islet cell tumors may be functional (the hormones that are released cause symptoms) or nonfunctional (the hormones that are released do not cause symptoms) tumors:

• Functional tumors make one or more hormones, such as gastrin, insulin, and glucagon, that cause symptoms. Most functional tumors are benign (not cancer).
• Nonfunctional tumors make hormones that do not cause symptoms. Symptoms are caused by the tumor as it spreads and grows. Most nonfunctional tumors are malignant (cancer).

There are different kinds of functional islet cell tumors.

Islet cells make different kinds of hormones such as gastrin, insulin, and glucagon. Types of functional islet cell tumors include the following:

• Gastrinoma: A tumor that forms in cells that make gastrin. Gastrin is a hormone that causes the stomach to release an acid that helps digest food. Both gastrin and stomach acid are increased by gastrinomas. When increased stomach acid, stomach ulcers, and diarrhea are caused by a tumor that makes gastrin, it is called Zollinger-Ellison syndrome. A gastrinoma usually forms in the head of the pancreas and sometimes forms in the small intestine. Most gastrinomas are malignant (cancer).
• Insulinoma: A tumor that forms in cells that make insulin. Insulin is a hormone that controls the amount of glucose (sugar) in the blood. It moves glucose into the cells, where it can be used by the body for energy. Insulinomas are usually slow-growing tumors that rarely spread. An insulinoma forms in the head, body, or tail of the pancreas. Insulinomas are usually benign (not cancer).
• Glucagonoma: A tumor that forms in cells that make glucagon. Glucagon is a hormone that increases the amount of glucose in the blood. It causes the liver to break down glycogen. Too much glucagon causes hyperglycemia (high blood sugar). Glucagonomas are often malignant. A glucagonoma usually forms in the tail of the pancreas. Most glucagonomas are malignant (cancer).
• Other types of tumors: There are other rare types of functional islet cell tumors that make hormones, including hormones that control the balance of sugar, salt, and water in the body. These tumors include:
  • VIPomas, which make vasoactive intestinal peptide. VIPoma may also be called Verner-Morrison syndrome.
  • Somatostatinomas, which make somatostatin.
  These other types of tumors are grouped together because they are treated in much the same way.

Having certain syndromes can increase the risk of developing islet cell tumors.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor.

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a risk factor for islet cell tumors.

Different types of islet cell tumors have different signs and symptoms.

Symptoms can be caused by the growth of the tumor and/or by hormones the tumor makes. Some tumors may not cause symptoms. Conditions other than islet cell tumors can cause the symptoms listed below. A doctor should be consulted if any of these problems occur.

Signs and symptoms of a non-functioning islet cell tumor

A non-functioning islet cell tumor may grow for a long time without causing symptoms. It may grow large or spread to other parts of the body before it causes symptoms, such as:

• Diarrhea.
• Indigestion.
• A lump in the abdomen.
• Pain in the abdomen or back.
• Yellowing of the skin and whites of the eyes.

A tumor that makes pancreatic peptides (PPoma) often has no symptoms.

Signs and symptoms of a functioning islet cell tumor

The symptoms of a functioning islet tumor depend on the type of hormone being made.

Too much gastrin may cause:

• Stomach ulcers that keep coming back.
• Pain in the abdomen, which may spread to the back. The pain may come and go and it may go away after taking an antacid.
• The flow of stomach contents back into the esophagus (gastroesophageal reflux).
• Diarrhea.

Too much insulin may cause:

• Low blood sugar. This can cause blurred vision, headache, and feeling lightheaded, tired, weak, shaky, nervous, irritable, sweaty, confused, or hungry.
• Feeling a fast heartbeat.

Too much glucagon may cause:

• Skin rash on the face, stomach, or legs.
• High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
• Blood clots in the lung. This can cause shortness of breath, cough or pain in the chest. Blood clots in the arm or leg can cause pain, swelling, warmth, or redness of the arm or leg.
• Diarrhea.
• Weight loss for no known reason.
• Sore tongue or sores at the corners of the mouth.

Too much vasoactive intestinal peptide (VIP) may cause:

• Very large amounts of watery diarrhea.
• Dehydration. This can cause feeling thirsty, making less urine, dry skin and mouth, feeling tired, headache, or dizziness.
• Low potassium level in the blood. This can cause muscle weakness, aching, or cramps, numbness and tingling, frequent urination, and feeling a fast heartbeat, confused, or thirsty.
• Cramps or pain in the abdomen.
• Weight loss for no known reason.

Too much somatostatin may cause:

• High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
• Diarrhea.
• Steatorrhea (very foul-smelling stool that floats).
• Gallstones.
• Yellowing of the skin and whites of the eyes.
• Weight loss for no known reason.

Lab tests and imaging tests are used to detect (find) and diagnose islet cell tumors.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as glucose (sugar), released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
• Serum tumor marker test: A procedure in which a sample of blood is checked to measure the amounts of certain substances released into the blood by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumor markers.
• Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.
• Abdominal CT scan (CAT scan): A procedure that makes a series of detailed pictures of the abdomen, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
• Abdominal ultrasound: An ultrasound exam used to make pictures of the inside of the abdomen. The ultrasound transducer is pressed against the skin of the abdomen and directs high-energy sound waves (ultrasound) into the abdomen. The sound waves bounce off the internal tissues and organs and make echoes. The transducer receives the echoes and sends them to a computer, which uses the echoes to make pictures called sonograms. The picture can be printed to be looked at later.
• Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body, usually through the mouth or rectum. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography.
• Angiogram: A procedure to look at blood vessels and the flow of blood. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if there are any blockages.
• Laparotomy: A surgical procedure in which an incision (cut) is made in the wall of the abdomen to check the inside of the abdomen for signs of disease. The size of the incision depends on the reason the laparotomy is being done. Sometimes organs are removed or tissue samples are taken and checked under a microscope for signs of disease.
• Intraoperative ultrasound: A procedure that uses high-energy sound waves (ultrasound) to create images of internal organs or tissues during surgery. A transducer placed directly on the organ or tissue is used to make the sound waves, which create echoes. The transducer receives the echoes and sends them to a computer, which uses the echoes to make pictures called sonograms.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. There are several ways to do a biopsy for islet cell tumors. Cells may be removed using a fine or wide needle inserted into the pancreas during an x-ray or ultrasound. Tissue may also be removed during a laparoscopy (a surgical incision made in the wall of the abdomen).
• Bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the blood. The radioactive material collects in bones where cancer cells have spread and is detected by a scanner.

Other kinds of lab tests are used to check for the different types of islet cell tumors.

The following tests and procedures may be used:

Gastrinoma

• Fasting serum gastrin test: A test in which a blood sample is checked to measure the amount of gastrin in the blood. This test is done after the patient has had nothing to eat or drink for at least 8 hours. Conditions other than gastrinoma can cause an increase in the amount of gastrin in the blood.
• Gastric acid secretion test: A test to measure the amount of acid made by the stomach. A tube is inserted through the nose or throat, into the stomach. Gastrin or insulin is injected into the patient, which causes the stomach to make stomach secretions (gastric acid). Four samples of gastric acid are taken through the tube 15 minutes apart. These four samples are used to find out the lowest and highest amounts of gastric acid made during the test and the pH level of the gastric secretions.
• Secretin stimulation test: If the gastric acid secretion test result is not normal, a secretin stimulation test may be done. The tube is moved into the small intestine and samples are taken from the small intestine after a drug called secretin is injected. Secretin causes the small intestine to make acid. When there is a gastrinoma, the secretin causes an increase in how much gastric acid is made and the level of gastrin in the blood.
• Calcium infusion test: A test to measure the amount of gastrin in the blood after a drug called calcium gluconate is infused. Blood samples will be taken to measure the amount of gastrin in the blood at set times.
• Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.

Insulinoma

• Fasting serum glucose and insulin test: A test in which a blood sample is checked to measure the amounts of glucose (sugar) and insulin in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
• C-peptide suppression test: A test in which a blood sample is checked to measure the amount of C-peptide in the blood. Insulin is injected into a vein to lower the patient’s blood sugar. This should decrease the amount of insulin and C-peptide that the body releases into the blood. In patients who have insulinoma, the insulin and C-peptide levels do not drop because the tumor is also releasing insulin and C-peptide into the blood.
• Venous sampling after arterial stimulation: A procedure used to help find where a tumor has formed in the pancreas. This is done at the same time as an angiogram. Calcium is injected into an artery that goes to one part of the pancreas (the head, body, and tail are tested one at a time). A blood sample is taken from a vein that comes out of the pancreas and is checked for pancreatic hormones. If there is an islet cell tumor in the area of the pancreas that gets blood from the artery that was injected, there will be an increase in the amount of hormone in the blood sample. If the increase is found after injection into the first artery, the tumor is in the area that gets blood from that artery. If there is no increase, another artery is injected and the test continues.
• Anti-insulin antibody test: A test in which a blood sample is checked to see if there are antibodies against insulin in it.

Glucagonoma

• Fasting serum glucagon test: A test in which a blood sample is checked to measure the amount of glucagon in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.

Other tumor types

• VIPoma
  • Serum VIP (vasoactive intestinal peptide) test: A test in which a blood sample is checked to measure the amount of VIP.
  • Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. In VIPoma, there is a lower than normal amount of potassium.
  • Stool analysis: A stool sample is checked for a higher than normal sodium (salt) and potassium levels.
• Somatostatinoma
  • Fasting serum somatostatin test: A test in which a blood sample is checked to measure the amount of somatostatin in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
  • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
• PPoma
  • Fasting serum polypeptide test: A test in which a blood sample is checked to measure the amount of pancreatic polypeptide in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
  • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
  • Atropine suppression test: A test used to help find out if the secretion of a polypeptide (protein) by the pancreas is normal or caused by a tumor. A drug called atropine, which can lessen secretions, is injected into a vein. After the injection, pancreatic polypeptide levels in the blood stay the same in patients with tumors, but drop in patients without tumors.
  • Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens.

Certain factors affect prognosis (chance of recovery) and treatment options.

Islet cell tumors can often be cured. The prognosis (chance of recovery) and treatment options depend on the following:

• The type of cancer cell.
• Where the tumor is found in the pancreas.
• Whether the tumor has spread to more than one place in the pancreas or to other parts of the body.
• Whether the patient has MEN1 syndrome.
• The patient's age and general health.
• Whether the cancer has just been diagnosed or has recurred (come back).

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Having to do with the abdomen, which is the part of the body between the chest and the hips that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

A chemical that gives off hydrogen ions in water and forms salts by combining with certain metals. Acids have a sour taste and turn certain dyes red. Some acids made by the body, such as gastric acid, can help the body work the way it should. An example of an acid is hydrochloric acid.

A process in which anything complex is separated into simple or less complex parts.

An x-ray of blood vessels. The person receives an injection of dye to outline the vessels on the x-ray.

A protein made by plasma cells (a type of white blood cell) in response to an antigen (a substance that causes the body to make a specific immune response). Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

Any substance that causes the body to make a specific immune response.

A blood vessel that carries blood from the heart to tissues and organs in the body.

Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called nonmalignant.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A procedure in which a sample of blood is examined to measure the amounts of certain substances made in the body. An abnormal amount of a substance can be a sign of disease in the organ or tissue that produces it.

A mass of blood that forms when blood platelets, proteins, and cells stick together. When a blood clot is attached to the wall of a blood vessel, it is called a thrombus. When it moves through the bloodstream and blocks the flow of blood in another part of the body, it is called an embolus.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner.

The mineral calcium, combined with a form of the sugar glucose. It is used to prevent and treat bone loss. It is also being studied in the treatment of bone loss and nerve damage caused by chemotherapy.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.

A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.

To heal or restore health; a treatment to restore health.

A condition caused by the loss of too much water from the body. Severe diarrhea or vomiting can cause dehydration.

The process of identifying a disease, such as cancer, from its signs and symptoms.

Frequent and watery bowel movements.

The process of breaking down food into substances the body can use for energy, tissue growth, and repair.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

In medicine, a tube or vessel of the body through which fluids pass.

A pancreatic cell that produces hormones (e.g., insulin and glucagon) that are secreted into the bloodstream. These hormones help control the level of glucose (sugar) in the blood. Also called islet cell and islet of Langerhans cell.

A thin, tube-like instrument used to look at tissues inside the body. An endoscope has a light and a lens for viewing and may have a tool to remove tissue.

A procedure in which an endoscope is inserted into the body. An endoscope is a thin, tube-like instrument that has a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal organs to make a picture (sonogram). Also called endosonography and EUS.

A protein that speeds up chemical reactions in the body.

The muscular tube through which food passes from the throat to the stomach.

A pancreatic cell that produces enzymes that are secreted into the small intestine. These enzymes help digest food as it passes through the gastrointestinal tract.

A tumor that is found in endocrine tissue and makes hormones (chemicals that travel in the bloodstream and control the actions of other cells or organs).

Solid material that forms in the gallbladder or common bile duct. Gallstones are made of cholesterol or other substances found in the gallbladder. They may occur as one large stone or as many small ones, and vary from the size of a golf ball to a grain of sand. Also called cholelith.

Having to do with the stomach.

A hormone released from special cells in the lining of the stomach after eating. Gastrin causes the stomach to release an acid that helps digest food.

A tumor that causes overproduction of gastric acid. It usually begins in the duodenum (first part of the small intestine that connects to the stomach) or the islet cells of the pancreas. Rarely, it may also begin in other organs, including the stomach, liver, jejunum (the middle part of the small intestine), biliary tract (organs and ducts that make and store bile), mesentery, or heart. It is a type of neuroendocrine tumor, and it may metastasize (spread) to the liver and the lymph nodes.

The backward flow of stomach acid contents into the esophagus (the tube that connects the mouth to the stomach). Also called esophageal reflux and gastric reflux.

An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.

A hormone produced by the pancreas that increases the level of glucose (sugar) in the blood.

A rare pancreatic tumor that produces a hormone called glucagon. Glucagonomas can produce symptoms similar to diabetes.

A type of sugar; the chief source of energy for living organisms.

One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.

Higher than normal amount of glucose (a type of sugar) in the blood. Hyperglycemia can be a sign of diabetes or other conditions. Also called high blood sugar.

A cut made in the body to perform surgery.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.

Having to do with the intestines.

A pancreatic cell that produces hormones (e.g., insulin and glucagon) that are secreted into the bloodstream. These hormones help control the level of glucose (sugar) in the blood. Also called endocrine pancreas cell and islet of Langerhans cell.

A mass of abnormal cells that forms in the endocrine (hormone-producing) tissues of the pancreas. Islet cell tumors may be benign (not cancer) or malignant (cancer).

A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

A procedure that uses a laparoscope, inserted through the abdominal wall, to examine the inside of the abdomen. A laparoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.

A surgical incision made in the wall of the abdomen.

A clear disk that focuses light, as in a camera or microscope. In the eye, the lens is a clear, curved structure at the front of the eye behind the pupil. It focuses light rays that enter the eye through the pupil, making an image on the retina (light-sensitive layers of nerve tissue at the back of the eye).

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

An instrument that is used to look at cells and other small objects that cannot be seen with the eye alone.

A procedure in which radio waves and a powerful magnet linked to a computer is used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.

A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors are usually benign (not cancer). They cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems, and severe ulcers. In some cases, tumors inside the pancreas can become malignant (cancer). Also called MEN1 syndrome, multiple endocrine adenomatosis, and Wermer syndrome.

A tumor that is found in endocrine tissue but that does not make extra hormones (chemicals that travel in the blood and control the actions of other cells or organs). Also called endocrine-inactive tumor.

A drug similar to the naturally occurring growth hormone inhibitor somatostatin. Octreotide is used to treat diarrhea and flushing associated with certain types of tumors.

A part of the body that performs a specific function. For example, the heart is an organ.

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called exocrine cancer.

A doctor who identifies diseases by studying cells and tissues under a microscope.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A molecule that contains two or more amino acids (the molecules that join together to form proteins). Peptides that contain many amino acids are called polypeptides or proteins.

An exam of the body to check for general signs of disease.

A metallic element that is important in body functions such as regulation of blood pressure and of water content in cells, transmission of nerve impulses, digestion, muscle contraction, and heartbeat.

The likely outcome or course of a disease; the chance of recovery or recurrence.

Giving off radiation.

An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radioisotopes may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radionuclide.

A procedure that produces pictures (scans) of structures inside the body, including areas where there are cancer cells. Radionuclide scanning is used to diagnose, stage, and monitor disease. A small amount of a radioactive chemical (radionuclide) is injected into a vein or swallowed. Different radionuclides travel through the blood to different organs. A machine with a special camera moves over the person lying on a table and detects the type of radiation given off by the radionuclides. A computer forms an image of the areas where the radionuclide builds up. These areas may contain cancer cells. Also called scintigraphy.

The last several inches of the large intestine closest to the anus.

To come back or to return.

Something that increases the chance of developing a disease. Some examples of risk factors for cancer are age, a family history of certain cancers, use of tobacco products, being exposed to radiation or certain chemicals, infection with certain viruses or bacteria, and certain genetic changes.

In medicine, an instrument that takes pictures of the inside of the body.

The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.

A blood test that measures the amount of substances called tumor markers (or biomarkers). Tumor markers are released into the blood by tumor cells or by other cells in response to tumor cells. A high level of a tumor marker may be a sign of cancer.

The part of the digestive tract that is located between the stomach and the large intestine.

A mineral needed by the body to keep body fluids in balance. Sodium is found in table salt and in many processed foods. Too much sodium can cause the body to retain water.

A type of radionuclide scan used to find carcinoid and other types of tumors. Radioactive octreotide, a drug similar to somatostatin, is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to tumor cells that have receptors for somatostatin. A radiation-measuring device detects the radioactive octreotide, and makes pictures showing where the tumor cells are in the body. Also called octreotide scan and SRS.

A computer picture of areas inside the body created by bouncing high-energy sound waves (ultrasound) off internal tissues or organs. Also called ultrasonogram.

The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone. The spine encloses the spinal cord and the fluid surrounding the spinal cord. Also called backbone, spinal column, and vertebral column.

An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.

The material in a bowel movement. Stool is made up of undigested food, bacteria, mucus, and cells from the lining of the intestines. Also called feces.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

The hollow tube inside the neck that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach). The throat is about 5 inches long, depending on body size. Also called pharynx.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

A substance that may be found in tumor tissue or released from a tumor into the blood or other body fluids. A high level of a tumor marker may mean that a certain type of cancer is in the body. Examples of tumor markers include CA 125 (in ovarian cancer), CA 15-3 (in breast cancer), CEA (in ovarian, lung, breast, pancreas, and gastrointestinal tract cancers), and PSA (in prostate cancer).

The formation of a break on the skin or on the surface of an organ. An ulcer forms when the surface cells die and are cast off. Ulcers may be associated with cancer and other diseases.

A procedure in which high-energy sound waves are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasonography.

A device that produces sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create a picture called a sonogram. Transducers (probes) come in different shapes and sizes for use in making pictures of different parts of the body. The transducer may be passed over the surface of the body or inserted into an opening such as the rectum or vagina.

Fluid containing water and waste products. Urine is made by the kidneys, stored in the bladder, and leaves the body through the urethra.

A blood vessel that carries blood to the heart from tissues and organs in the body.

A procedure in which a sample of blood is taken from a certain vein and checked for specific substances released by nearby organs and tissues. A higher than normal amount of a substance can be a sign of disease in the organ or tissue that makes it.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.

A disorder in which tumors of the pancreatic islet cells produce large amounts of gastrin (a hormone), leading to excess acid in the stomach and, possibly, a peptic ulcer (ulcer of the stomach or the upper part of the small intestine).