Endocrine Abstracts

Insulinoma, a pancreatic β-cell tumor, comprises 55% of Neuroendocrine tumors with an annual incidence of 3–10/million. Female to male ratio is 3:2 presenting in their 4th decade. The main clinical symptom is severe hypoglycemia irrespective of tumor size.

Aim: Presentation of four newly diagnosed insulinoma patients aged 18–60, within an eight month interval.

All patients presented with neuroglycopenic symptoms (irritability, emotional lability, sluggish speech, blurred vision). On admission one patient presented with semicoma, another with acute coronary syndrome, the third had a car accident and hypoglycemia was an incidental finding in the fourth. All patients underwent prolonged fasting test. Whipple’s triad, insulin glucose ratio>0.4, c-peptide>2.5 ng/ml during hypoglycemia established the diagnosis. CT and MRI scan of the abdomen revealed hypervascular lesions with intense arterial phase enhancement in the pancreas (three patients). Multiple metastatic hepatic lesions without a primary pancreatic tumor (no pancreatic lesions) were found in the fourth patient (malignant insulinoma). Chromogranin A was marginally increased only in the malignant insulinoma patient. All patients were treated initially with intravenous glucose, Diazoxide and somatostatin analogue. Two patients underwent peripheral pancreatectomy with complete remission of their hypoglycemia. One patient is scheduled for surgery. The fourth patient underwent partial hepatectomy, hepatic chemoembolism and pancreatectomy, with marked improvement of his symptoms. Ninety percent of insulinomas are benign, 10% are malignant, 10% are multiple and 50% of them present in MEN1. Benign or malignant insulinomas cannot be histologically differentiated. Surgery is the treatment of choice for benign, malignant or recurrent disease.

Conclusion: High clinical suspicion is a prerequisite for the diagnosis and treatment of these slow growing usually benign tumors. The sudden cluster of four insulinomas over an 8 month period in our department with complete absence of cases over the past 23 years demands increased vigilance in case this is a non-random but a causal effect in need of further elucidation.