Glucagonomas are a type of rare neuroendocrine tumor that grows in parts of your body that are responsible for releasing hormones. In particular, glucagonomas affect cells in your pancreas that produce a hormone called glucagon, which helps regulate your blood sugar levels.
Glucagonomas are functional tumors, meaning they produce hormones like normal cells, but often much more than your body needs.
High levels of glucagon from a pancreatic glucagonoma can lead to serious health problems. If you have symptoms, it's referred to as glucagonoma syndrome.
Here's what you need to know about glucagonoma symptoms, diagnosis, risks, treatments, and possible outcomes.
What Are the Symptoms of a Glucagonoma?
Your pancreas makes glucagon when you have low blood sugar. This hormone sends a signal to your liver to break down glycogen (a stored form of glucose) in order to increase your blood sugar.
Glucagonoma tumors produce excessive amounts of glucagon, which will make your blood sugar levels rise. Some symptoms of glucagonoma syndrome include:
Type 2 diabetes. This affects about 80% of people with glucagonoma syndrome. The high blood sugar levels from the tumors cause many people with glucagonomas to have the same symptoms as people with diabetes.
Dermatosis. A skin rash happens in up to 90% of people with glucagonomas. The rash is called necrolytic migratory erythema and can be itchy or painful. It usually begins in parts of your body with creases — most commonly your groin area — and will spread from there. It looks red and blotchy, with dry, crusty, white, or yellow patches.
Weight loss. Increased glucagon levels will often cause weight loss. Roughly 90% of people with glucagonomas will experience some weight loss.
Deep vein thrombosis (DVT). This happens when blood clots form in the deep veins of your legs. Almost 50% of people with glucagonomas have DVT.
Chronic diarrhea. About 30% of people with glucagonoma will experience chronic diarrhea.
Other glucagonoma symptoms include anemia (a low number of red blood cells), a swollen or inflamed tongue, sores around the mouth (glossitis), and chapped lips.
Glucagonoma syndrome has also been linked to mental health problems. Depression is the most common, with about 50% of people with glucagonomas reporting it.
How Are Glucagonomas Diagnosed?
Your doctor can diagnose glucagonoma syndrome using a combination of physical exams, blood tests, and imaging scans. Your doctor will evaluate your symptoms and check your glucagon levels.
An ultrasound, MRI, or CT scan can be used to see any tumors affecting your pancreas. Most glucagonomas are over 3 centimeters in diameter, making them easy to see during the imaging scan.
How Are Glucagonomas Treated?
Glucagonoma treatment often begins with managing symptoms. Weight loss, high blood sugar levels, skin rashes, and blood clots are each treated to temporarily improve symptoms.
Glucagonoma tumors that have not spread (metastasized) can often be removed surgically. After surgery, the skin rash will start to heal within a few days and other symptoms will also disappear.
Certain cancer drugs can be used to treat tumors that can't be safely removed, or that have spread to other parts of your body. Around 80% of glucagonomas are cancerous, and most commonly spread to the liver.
If you have a tumor that has spread to other parts of your body, your glucagonoma syndrome symptoms will continue to be treated. Octreotide is a medication that can help regulate and prevent high levels of glucagon. Octreotide injections help reduce some glucagonoma side effects like high blood sugar and weight loss.
Who Is at Risk for Glucagonomas?
Glucagonomas are rare.
People with a family history of multiple endocrine neoplasia type 1 (MEN-1), a disorder that causes tumors to grow in endocrine glands, have a greater risk of getting neuroendocrine tumors like glucagonomas. About 10% of glucagonomas are diagnosed in people with MEN-1.
People with glucagonomas are usually over age 50 and are mostly female: Roughly 80% of glucagonomas are found in women.
What Are the Survival Rates From a Glucagonoma?
Glucagonoma tumors are slow growing, but their symptoms are often similar to other diseases. That means they may not be discovered until they have grown.
Over 50% of glucagonomas will have spread to other parts of your body by the time they're diagnosed. Cancer from glucagonomas will most often spread to your liver. The earlier you're diagnosed with glucagonoma, the greater your chance of a good outcome.
People with cancers from glucagonomas that spread to other body parts -- have about a 50% chance of living 10 years after diagnosis. For people with glucagonomas that have not spread and can be surgically removed, their 10-year survival rate doubles to almost 100%.