Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Insulinoma

By

Anthony Villano

, MD, Fox Chase Cancer Center

Reviewed/Revised Oct 2023
VIEW PROFESSIONAL VERSION
Topic Resources

Only 10% of insulinomas are cancerous. The average age at diagnosis is 50.

The Pancreas
VIDEO

Symptoms of Insulinoma

Symptoms of insulinoma result from low levels of sugar (glucose) in the blood (hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more ), which occur when the person does not eat for several hours (most often in the morning after an all-night fast). The symptoms include faintness, weakness, trembling, awareness of the heartbeat (palpitations), sweating, nervousness, and profound hunger.

Other symptoms include headache, confusion, vision abnormalities, unsteadiness, and marked changes in behavior or thinking.

The low levels of sugar in the blood may even lead to a loss of consciousness, seizures, and coma.

Diagnosis of Insulinoma

  • Blood tests

  • Imaging tests

Diagnosing an insulinoma can be difficult. Doctors try to do blood tests while the person has symptoms and has not eaten. Blood tests include measurements of blood glucose levels and insulin levels. Very low levels of glucose and high levels of insulin in the blood indicate the presence of an insulinoma. Because many people have symptoms only occasionally, doctors may admit them to the hospital. In the hospital, the person fasts for at least 48 hours, sometimes up to 72 hours, and is closely monitored. During that time, the symptoms usually appear, and blood tests are done to measure the levels of glucose and insulin.

Treatment of Insulinoma

  • Surgical removal

  • Diazoxide or sometimes octreotide

  • Sometimes chemotherapy

The primary treatment for an insulinoma is surgical removal, which has a cure rate of about 90%.

When the insulinoma cannot be completely removed and symptoms continue, medications such as diazoxide or sometimes octreotide can help keep blood glucose from falling too low.

Chemotherapy drugs may help control the tumor.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Hyperstat, Proglycem
Bynfezia, Mycapssa, Sandostatin, Sandostatin LAR
NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
quiz link

Test your knowledge

Take a Quiz!
iOS ANDROID
iOS ANDROID
iOS ANDROID
TOP