Is an Insulinoma?
An insulinoma is
a small tumor in the pancreas that produces an excess amount of insulin. In
most cases, the tumor isn’t cancerous. Most insulinomas are less
than 2 centimeters in diameter.
The pancreas is an endocrine organ located behind your stomach.
One of its functions is to produce hormones that control the level of sugar in your
bloodstream, such as insulin. Normally, the pancreas stops creating insulin
when your blood sugar drops too low. This allows your blood sugar levels to
return to normal. When an insulinoma forms in your pancreas, however, it will
continue to produce insulin, even when your blood sugar is too low. This can
lead to severe hypoglycemia, or
low blood sugar. Hypoglycemia
is a dangerous condition that can cause blurred vision, lightheadedness, and unconsciousness.
It can also be life-threatening.
An insulinoma usually needs to be surgically removed. Once the
tumor is removed, complete recovery is very likely.
Are the Symptoms of an Insulinoma?
People with insulinomas don’t always have noticeable symptoms. When
symptoms do occur, they can vary depending on the severity of the condition.
Mild symptoms include:
- double vision or blurred vision
- anxiety and irritability
- mood swings
- sudden weight gain
More severe symptoms of insulinoma can affect the brain. They can
also affect the adrenal glands, which regulate stress response and heart rate.
Sometimes, symptoms seem similar to those of epilepsy, a neurological disorder that causes seizures. Symptoms
that are seen in more serious cases of insulinoma may include:
- convulsions or seizures
- a rapid heart rate (greater than 95 beats per
- difficulty concentrating
- loss of consciousness or coma
In some cases, insulinomas can get bigger and spread to other
parts of the body. When this occurs, you can get the following symptoms:
- abdominal pain
- back pain
- jaundice, or yellowing of the skin and eyes
Causes an Insulinoma?
Doctors don’t know exactly why people get insulinomas. The tumors
typically show up without warning.
When you eat food, the pancreas creates insulin. Insulin is a
hormone that helps your body store the sugar from your food. Once the sugar has
been absorbed, the pancreas stops producing insulin. This process usually keeps
blood sugar levels stable. However, it can be disrupted when an insulinoma
develops. The tumor continues to produce insulin even when your blood sugar
drops too low. This can lead to hypoglycemia, a serious condition characterized
by low blood sugar levels.
Is at Risk for an Insulinoma?
Insulinomas are rare. Most are small and measure less
than 2 centimeters in diameter. Only 10
percent of these tumors are cancerous. Cancerous tumors tend to occur more
often in people who have multiple endocrine neoplasia type 1. This is an
inherited disease that causes tumors in one or more hormonal glands. The risk for
insulinoma also seems to be higher for those with von Hippel-Lindau syndrome. This
inherited condition causes tumors and cysts to form throughout the body.
Insulinomas also tend to affect women more than men. They most
commonly develop in people who are between ages 40 and 60.
Is an Insulinoma Diagnosed?
Your doctor will perform a blood test to check your blood sugar
and insulin levels. A low blood sugar level with a high insulin level indicates
the presence of an insulinoma.
The test can also check for:
- proteins that block the production of insulin
- medications that cause the pancreas to release
- other hormones that affect insulin production
Your doctor may order a 72-hour fast if the blood test indicates that
you have an insulinoma. You’ll stay in the hospital while you fast so your
doctor can monitor your blood sugar levels. They’ll measure your blood sugar
levels every six hours at least. You won’t be able to eat or drink anything
except water during the fast. You’ll likely have very low blood sugar levels
within 48 hours of starting the fast if you have an insulinoma.
Your doctor may perform more tests to confirm the diagnosis,
including an MRI or CT scan.
These imaging tests help your doctor determine the location and size of the
ultrasound may be used if the tumor can’t be found using a CT or
MRI scan. During an endoscopic ultrasound, your doctor inserts a long, flexible
tube into your mouth and down through the stomach and small intestine. The tube
contains an ultrasound probe, which emits sounds waves that produce detailed
images of your pancreas. Once the insulinoma is located, your doctor will take
a small sample of tissue for analysis. This can be used to determine whether
the tumor is cancerous.
Is an Insulinoma Treated?
The best treatment for an insulinoma is surgical removal of the
tumor. A small part of the pancreas may also be removed if there’s more than
one tumor. This typically cures the condition.
There are various types of surgery that can be performed to
remove the insulinoma. The location and number of tumors determine which surgery
will be used.
Laparoscopic surgery is
the preferred option if there’s only one small pancreatic tumor. This is a low-risk, minimally invasive
procedure. During laparoscopic surgery, your surgeon makes several
small incisions in your abdomen and inserts a laparoscope through the incisions. A laparoscope is a
long, thin tube with a high-intensity light and a high-resolution camera at the
front. The camera will display the images on a screen, allowing the surgeon to
see inside your abdomen and guide the instruments. When the
insulinoma is found, it will be removed.
Part of the pancreas may need to be removed if there are multiple
insulinomas. Sometimes, part of the stomach or liver may be removed as well.
In rare cases, removing the insulinoma won’t cure the condition. This
is usually true when the tumors are cancerous. Treatments for cancerous
- radiofrequency ablation, which uses radio waves
to kill cancerous cells in the body
which involves the use of extreme cold to destroy cancerous cells
- chemotherapy, which is
an aggressive form of chemical drug therapy that helps destroy cancerous cells
Your doctor may also prescribe medications to control blood sugar
levels if surgery wasn’t effective.
Is the Long-Term Outlook for People with an Insulinoma?
The long-term outlook for people with an insulinoma is very good
if the tumor is removed. After surgery, most people recover completely without complications.
However, an insulinoma may return in the future. Recurrence is more common in people
who have multiple tumors.
A very small number of people may develop diabetes after surgery.
This usually only occurs when the entire pancreas or a large portion of the
pancreas is removed.
Complications are more likely in people with cancerous
insulinomas. This is particularly true when the tumors have spread to other
organs. The surgeon may not be able to remove all the tumors completely. In
this case, more treatment and follow-up care will be necessary. Luckily, only a
small number of insulinomas are cancerous.
Can an Insulinoma Be Prevented?
Doctors don’t know why insulinomas form, so there’s no known way
to prevent them. However, you can reduce your risk of developing hypoglycemia
by exercising regularly and maintaining a healthy diet. This diet should
largely consist of fruits, vegetables, and lean protein. You can also keep your
pancreas healthy by eating less red meat and quitting smoking if you smoke.