Introduction: Insulinoma is a rare endocrine pancreatic tumor that is derived from beta cells and produces insulin. Clinically it presents with hypoglycemia, weakness, blurred vision, palpitation, and unconsciousness resulting from endogenous hyperinsulinism.
Materials and Methods: A 47-year-old man presented to the Internal Medicine Department with hypoglycemia (1.1 mmol/l), weakness, loss of appetite for a few days, blurred vision and a loss of consciousness. His past medical history included chronic pangastritis, chronic colitis, hypoglycemia (1.6,…2.3 mmol/l), severe weight loss in the past 5 years and episodes of unconsciousness on several occasions.
The hematology and biochemistry tests were normal except for the low blood glucose level (2.6 mmol/l). A fasting test was performed and the levels of insulin and blood glucose were measured at the same time, giving the ratio > 3.5 which speaks in favour of an inappropriate insulin secretion. In order to localise the tumor, an MRI of the abdomen and CT - enterography were performed, both of which showed pathological induration of the wall of jejunum. For a more precise diagnosis an octreoscan is to be performed.
The patient was treated with glucose, diazoxide, hydrochlorothiazide and prepared for surgical intervention.
Results: The differential diagnoses include insulinoma, noninsulinoma pancreatogenic hypoglycemia syndrome (NIPHS), gastrinoma and VIPomas. Elevated insulin level, hypoglycemia and failure of endogenous insulin suppression by hypoglycemia are the hallmark of an insulinoma and disprove other diagnoses.
Conclusion: Most insulinomas are benign tumors and have a good prognosis.
Treatment in the long-term consists of complete resection of the tumor.
