RESUMEN
Insulinoma is the most frequent functional neuroendocrine tumor of the pancreas, which causes organic hyperinsulinism with severe hypoglycemia. There are no cases of primary insulinoma of the liver described. A 63-year-old female was admitted to our center presenting symptoms of severe hypoglycemia due to confirmed endogenic hyperinsulinism. None of the performed diagnostic procedures could reveal a pancreatic tumor. However, a pathologic mass in the sixth segment of the liver was detected. We performed arterial calcium stimulation that showed increased levels of insulin and c-peptide in almost all stimulated arteries. The highest and most prolonged peaks were detected at the points of the common hepatic artery and the right hepatic artery. After the surgical removal of the liver tumor, the blood glucose level was stabilized within the normal range. Post-operative pathomorphological investigation confirmed the diagnosis of a neuroendocrine tumor. The long-term survival results show correct treatment tactics without any signs of disease recurrence.