Insulinoma is a rare tumor that starts in the endocrine cells in your pancreas. Endocrine cells prevent high blood sugar. Healthcare providers use surgery to remove insulinomas and cure the condition.
Insulinoma is one of several pancreatic neuroendocrine tumors (pNET) or islet cell tumors. These are rare tumors that start in your pancreas’ endocrine cells. They affect the endocrine cell that releases insulin, the hormone that keeps your blood sugar (blood glucose) levels from getting too high. More than 90% of insulinomas are benign tumors, meaning they don’t spread outside of your pancreas. Healthcare providers use surgery to remove insulinomas and cure the condition.
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Approximately 4 in 1 million people develop insulinomas. Most people are ages 40 to 50 when they’re diagnosed.
Insulinomas release insulin, the hormone that keeps your blood sugar from dropping. If you have an insulinoma, your body might be flooded with insulin. When that happens, you may feel (and look shaky). You may feel like your heart is racing. In very extreme circumstances, you may faint or have seizures.
Yes, insulinomas can become malignant, meaning they can spread from your pancreas to other areas of your body. Malignant insulinomas usually spread to your liver or lymph nodes. But malignant insulinomas are extremely rare.
If you have diabetes, it means your pancreas isn’t making enough insulin to maintain a healthy blood sugar level or your body isn’t processing the insulin your pancreas makes and releases. When that happens, your blood sugar level increases. If you have insulinoma, your body is making too much insulin, causing your blood sugar levels to drop.
Pancreatic cancer is cancer in your pancreas itself. When people talk about pancreatic cancer, they’re usually referring to adenocarcinoma of the pancreas, which usually develops in your pancreas’ ducts. Insulinoma is a neuroendocrine tumor in the beta (endocrine) cells in your pancreas.
Every person’s situation is different, so researchers may not know the specific cause every time someone develops insulinoma. But insulinoma is associated with the following syndromes and conditions:
Insulinomas make insulin, the hormone that lowers your blood sugar levels. When an insulinoma releases too much insulin, your blood sugar level dips, causing the following symptoms:
Healthcare providers use several tests to diagnose insulinoma, starting with a physical exam and medical history. They’ll ask about your specific symptoms, if your symptoms come and go, how long you’ve had the symptoms and if your symptoms are getting worse.
If you’re having symptoms, your healthcare provider may ask you to have a blood glucose test:
Your healthcare provider will probably do one or more of the following imaging tests to assess your tumor’s size and its location in your pancreas:
If imaging tests don’t provide enough information, your healthcare provider may decide to obtain samples of your pancreas’ tissue and cells so they can examine the tissue and cells under a microscope. Those tests may include:
Grading or staging is the process healthcare providers use to estimate how quickly a pNET like insulinoma might spread. They examine cells under a microscope, comparing the difference in appearance between normal and abnormal cells. They also check whether abnormal cells appear to be multiplying. Here is information about pNET grades or stages:
Yes, most insulinomas can be cured with surgery. One study showed 88% of people who had surgery for insulinoma were alive 10 years after diagnosis. Your healthcare provider will consider factors such as your tumor’s size and location before recommending a specific surgery. Surgical options include:
Yes, healthcare providers may choose to combine surgery with medical or nonsurgical treatments or use medical treatments when surgery isn’t an option. Your healthcare provider might recommend:
There’s a wide range of pNET treatments, from major surgery to chemotherapy. Talk to your healthcare provider about your treatment options and potential side effects.
Unfortunately, there aren’t steps you can take to reduce your risk. Insulinomas happen when the endocrine cells in your pancreas that create insulin begin multiplying uncontrollably, and researchers aren’t sure why that happens.
That said, insulinoma is associated with certain inherited conditions. If you know your family medical history includes inherited conditions, ask your healthcare provider if your family medical history puts you at risk of insulinoma.
While you may not be able to prevent developing an insulinoma, you can keep them from affecting your health. You can do that by keeping track of changes in your body, including signs you have low blood sugar.
Your condition can be cured if the tumors are diagnosed and treated with surgery to remove them. If you’ve been diagnosed with insulinoma, your healthcare provider may recommend you change your diet as well.
Most insulinomas are treated with surgery to remove the tumor or parts of your pancreas. Ask your healthcare provider what you can and can’t do as you recover from your surgery.
Insulinoma is one of several pNET types, and pNETs have common symptoms, like fatigue — feeling extremely tired day after day — and diarrhea, that you might have to manage throughout your treatment. Try to get as much rest as you can. If diarrhea is an issue, talk to your healthcare provider about ways to reduce its frequency and severity. Here are some other suggestions that might be helpful:
You should see your healthcare provider if your treatment side effects become worse. For example, if you had surgery, you should contact your healthcare provider if you have pain that persists despite taking prescribed pain medication.
You also should contact your healthcare provider if notice changes in your body that resemble your symptoms, particularly low blood sugar symptoms. These changes might be unrelated to your condition, and the best way to be sure of that is to talk to your healthcare provider.
Your healthcare provider may also recommend you have follow-up examinations three to four months after your surgery.
If you have insulinoma, you likely had surgery to remove your tumor. While most surgeries are uneventful, you should go to the emergency room any time you have the following symptoms:
You may be surprised and a little alarmed to learn you have a rare disease. Questions you might want to ask your healthcare provider include:
A note from Cleveland Clinic
Insulinomas are rare tumors that develop in your pancreas’ endocrine cells. Fortunately, surgery to remove your insulinoma almost always cures your condition. Even so, it’s not easy to learn you have a rare illness that requires surgery. Talk to your healthcare provider about your treatment plan, including your treatment options and treatment side effects. That way, you’ll know what to expect and what you can do to support your recovery from surgery and any other treatment.
Last reviewed by a Cleveland Clinic medical professional on 12/17/2021.
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