Generality
Insulinoma is a tumor that affects the pancreas, in particular the cells involved in the synthesis of insulin. Of all, insulinoma is the most frequent endocrine tumor of the pancreas, malignant in about 5-15% of cases.
As a result of this tumor process, the pancreatic β cells of the islets of Langerhans synthesize and release excessive amounts of insulin into the circulation, with an "inevitable drop in glycemic levels, especially in fasting conditions.
Symptoms
To learn more: Insulinoma Symptoms
Continued carbohydrate intake to control hypoglycemia often results in patient weight gain. Insulinoma symptoms worsen after exercise, alcohol, low calorie diets, and sulfonylurea treatment.
Hypoglycemic crises are corrected with the administration of simple carbohydrates; as soon as the crisis is resolved, foods richer in proteins and carbohydrates with a medium and low glycemic index will be eaten.
Insulinoma is a fairly rare tumor, given that its incidence is estimated in one case in 250,000 individuals per year. Generally insulinoma is single and small (<2 cm), and only in about 10% of patients recognize multiple insulinomas. It mainly affects adult males between the third and sixth decade of age.
Diagnosis
The diagnosis of insulinoma is mostly based on blood tests; it is positive when particularly high levels of insulin, C-peptide and proinsulin are shown on a blood sample taken after a prolonged fast, compared to low glycemic values.
Traditional imaging methods (CT scan, ultrasound and nuclear magnetic resonance) provide a limited diagnostic contribution, given the difficulties in identifying these neoplasms, especially due to their particularly small size.
For diagnostic purposes, specific drugs can instead be administered to stimulate the release of insulin by neoplastic pancreatic β cells. Sometimes, we proceed with the selective injection of a hyperosmolar solution of calcium inside the artery that supplies the pancreatic region where the insulinoma is localized; the intra-arterial injection of calcium determines the release of large concentrations of insulin inside the portal system, therefore in the hepatic veins, which can be precisely dosed by sampling.
Treatment
The treatment of insulinoma mainly involves the surgical removal of the pancreatic tract affected by the tumor; the operation must preserve at least 15% of the gland so that it can produce sufficient quantities of enzymes and hormones.
In subjects who cannot undergo this type of intervention, or in cases where the insulinoma cannot be completely removed, insulin secretion is reduced by administering the drug diazoxide (100-200 mg per os x 2-3 intakes / day; 12 mg / kg body weight in children).
This medicine is often accompanied by a diuretic to prevent water retention problems. Other drugs that can be used are octeocride, glucocorticoids, phenytoin and calcium antagonists. When possible, however, the removal of the insulinoma is decisive in the majority of patients.
