What is a Pancreatic Islet Cell Tumor?
A pancreatic islet cell tumor is a tumor that develops in the pancreas from a type of cell called an islet cell. These cells are responsible for manufacturing and releasing various hormones into the bloodstream. A tumor of islet cells can be benign (noncancerous) or malignant (cancerous) and can result in an overproduction of certain hormones, depending on the type of tumor.
An islet cell tumor is rare, but can cause a variety of symptoms depending upon the type of hormone that it produces. If the tumor is malignant and spreads to other parts of the body, the cancer can become very serious.
Other names for a pancreatic islet cell tumor are islet of Langerhans tumor, pancreatic endocrine tumor, and neuroendocrine tumor.
Types of Pancreatic Islet Cell Tumors
Islet cell tumors are either functional or nonfunctional.
Nonfunctional islet cell tumors produce substances that do not cause symptoms. The only symptoms are those that result from the growth and spread of the tumor. These are usually malignant.
Functional tumors are those that produce a hormone that results in symptoms. The three main types of functional tumors are gastrinomas, insulinomas, and glucagonomas.
A gastrinoma occurs when the tumor grows from islet cells that make the hormone gastrin. Gastrin helps to release acid in the stomach for food digestion.
An insulinoma is a tumor that produces the hormone insulin. Insulin is responsible for controlling sugar in the bloodstream.
A tumor that produces the hormone glucagon is a glucaganoma. This hormone causes the liver to release glucose, or sugar, into the bloodstream.
Rare Functional Tumors
A few types of functional islet cell tumors are extremely rare. These include VIPomas, which produce vasoactive intestinal peptide (VIP), and somatostatinomas, which make the hormone somatostatin. These hormones control sugar, water, and salt levels in the body.
What Are the Risk Factors for Developing Pancreatic Islet Cell Tumors?
Islet cell tumors are a very rare type of tumor. The only known risk factor for developing such a tumor is having a disease called multiple endocrine neoplasia type 1 syndrome (MEN1) or having a family history of the syndrome. MEN1 is a heritable disease that causes one or more endocrine glands to be overactive or to grow a tumor. The endocrine glands that can be affected by MEN1 include the pancreas, parathyroid, and pituitary gland.
What Are the Symptoms of Islet Cell Tumors?
The symptoms that result from having an islet cell tumor vary depending on the type. Symptoms from nonfunctional tumors arise from the growth and spread of the tumor. Symptoms of functional tumors depend on the hormone produced and released into the bloodstream.
- abdominal or back pain
- abdominal lump
- yellowing skin and eye whites
- recurring stomach ulcers
- abdominal pain that responds to antacids
- stomach contents flowing back up the esophagus
- low blood sugar, which causes headache, lightheadedness, blurred vision, weakness, shaking, irritability, and hunger
- elevated heartbeat
- rash on stomach, legs, or face
- high blood sugar, which results in headaches, dry skin, frequent urination, hunger, and thirst
- blood clots, which cause shortness of breath, chest pain, and cough, or arm and leg pain, swelling, and warmth
- unexplained weight loss
- tongue and mouth sores
How Are Islet Cell Tumors Diagnosed?
There are several ways your doctor may diagnosis an islet cell tumor. The first step is to complete an overall physical and check of medical and family history. The next step is to either run a blood test or perform an imaging technique to look for a tumor.
Blood tests look for increased levels of hormones such as insulin, glucagon, and gastrin, as well as glucose levels in the bloodstream. These levels can indicate an islet cell tumor.
Imaging tests allow your doctor to visualize your pancreas and look for the presence of a tumor. These tests may include an ultrasound, magnetic resonance imaging, or computed tomography, also called a CT scan. Another way of imaging the pancreas is to perform minor exploratory surgery. Your doctor may want to insert a small endoscope to view your pancreas or to take a small sample of the tissue for a biopsy.
Treatments for Islet Cell Tumors
Cancerous tumors are most often treated by surgery. The purpose of the surgery is to remove as much of the tumor as possible. If the tumor has spread to other areas of the body, such as the liver, it may be removed from those locations as well.
If the cancer is widespread throughout the body, chemotherapy may be used to decrease the size of the tumors.
When an islet cell tumor is benign (typically in the case of a functional tumor) treatment may simply involve medications that treat the symptoms of the overproduced hormone. If the symptoms are severe, surgery to remove the tumor may be performed.
Long-Term Outlook for Islet Cell Tumors
If a cancerous tumor is detected before it has spread beyond the pancreas, the prognosis is good. Surgery to remove it usually cures the cancer. The more the cancer cells have spread throughout the body, the smaller the chances of recovery are.
If the tumor is benign, prognosis is also good. Surgery can usually remove the tumor and cure the disease. Medications can relieve symptoms brought about by excess hormones.