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What is an insulinoma?

Insulinoma is a tumor of the pancreas that produces excessive amounts of insulin. Insulinomas are more common in women. The tumors are usually small (less than 2cm) and more than 90% of all insulinomas are benign (non-cancerous).

Insulinomas produce excessive amounts of insulin and this causes low blood sugar. The typical symptoms that patients complain about are related to the development of low bloods sugar and include tiredness, weakness, tremulous and hunger. Many patients have to eat frequently to prevent symptoms from the low blood sugar. Some patients may develop psychiatric symptoms because of the low blood sugar.

How is the diagnosis is made?

The diagnosis is made by simultaneous measurements of blood sugar and insulin levels in the blood. A low blood sugar with a high insulin level confirms the diagnosis. Once the diagnosis made based on the biochemical analysis then the physician will perform further studies to detect the tumor in the pancreas.

Since most of these tumors are small, detection of the tumor in the pancreas may be difficult. Some of the studies that are performed to detect the tumor include a detailed CT scan, MRI, octreotide scan, and an endoscopic ultrasound.

An experienced surgeon often detects these tumors even where they are not seen on radiological testing prior to surgery. Imaging the pancreas during the surgery directly with an ultrasound detects the majority of these tumors.

How is insulinoma treated

Insulinoma is a benign tumor of the pancreas in 90% of patients and removal of the tumor cures the patient of the symptoms. Surgical removal of the tumor is the treatment of choice. More than 90% of patients will not require any further treatment after removal of the tumor. The operations that are usually performed for removing the insulinoma include:

  • Enucleation: In this procedure the surgeon removes only the tumor preserving the rest of the pancreas. Since insulinomas usually occur on the surface of the pancreas and are covered by a capsule, they can be completely removed without having to remove any of the surrounding pancreas. At USC we have developed a laparoscopic procedure for enucleation of pancreatic insulinoma.The recurrence rate after enucleation of the insulinoma is very low and this is the treatment of choice if it is technically possible to perform this operation.
  • Pancreatic resection (removal): Less commonly the surgeon may remove part of the pancreas where the tumor is located by utilizing operative procedures such as a distal pancreatectomy or a Whipple operation. These operations are performed as an exception rather than commonly since the vast majority of the tumors can be removed with enucleation.
  • Laparoscopic operations: At USC we offer a laparoscopic procedure for removing pancreatic insulinoma. The operation of enucleation of the insulinoma is performed laparoscopically. With laparoscopic surgery the post-operative recovery period and amount of pain is reduced, hospital stay is shorter and patients are able to return to their normal activity much faster.

Contact information: USC Center for Pancreatic and Biliary Diseases
1510 San Pablo Street, Los Angeles, CA
1-855-724-7874 dde-mail:
Programs: pancreatic cancer, pancreatitis, laparoscopic surgery, endocrine surgery,
biliary surgery

This web site provides select information about pancreatic and biliary disorders and is updated twice monthly. This information is not intended as a substitute for professional medical consultation with your physician.It is important that you consult with your physician for detailed information about your medical condition and treatment.The center will make every effort to update the site, however, past performance is no guarantee of future medical outcomes.
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