Insulinoma is a rare tumor that arises from pancreatic cells. It may not be always malignant but even a benign insulinoma can threaten its carrier be recurring hypoclycemic conditions. The majority of insulinomas occur in the pancreatic tissue, but rarely, they may occur elsewhere in the body.


The cause of insulinoma occurrence is not clear. There is probably some role of genetic predisposition but this issue is still investigated.


Insulinoma manifests by excessive production of insulin by the tumor cells. Insulin is released into the bloodstream and causes too sharp decrease of blood sugar - recurring hypoglycemia. The symptoms include excessive sweating, palpitations, hand tremor, restlessness, confusion and its severe forms even unconsciousness. The majority of symptoms are related to inadequate intake of sugar in the brain. Prolonged overproduction of insulin can lead to a weight gain. Malignant forms of insulinoma may give rise to metastases.


Hypoglycemia can be easily confirmed by a blood test, modern glucometers need just a single drop of blood. Recurrent hypoglycemic state in a relatively healthy person, who is not treated with diabetes, is very suspicious of insulinoma. Blood tests may also help to evaluate the concentration of insulin and its decay products (in case of insulinoma, there is a chance that both values will be elevated). Sometimes a “fasting test” is used when the patient tends to be unable to maintain sufficient glycemia when fasting for few days. The tumor itself can be found by imaging methods such as abdominal ultrasound, computed tomography or nuclear medicine imaging.


Acute hypoglycemia is classically treated by administration of sugar, in ideal case in form of intravenous solution. The tumor is usually removable with a surgical intervention, sometimes in combination with chemotherapy. The intervention is not simple and it includes removal of part of pancreas as well. If the patient is unable to undergo the operation, some special drugs may be regularly administered that inhibit the production of insulin by the tumor.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources