Background: Insulinomas, the most common functional neuroendocrine tumours of the pancreas, are usually sporadic, benign and solitary.
Aims: To assess biochemical data, localisation and treatment outcome of insulinomas diagnosed in a tertiary endocrine centre.
Patients and methods: Twenty-five patients (14 F/11 M), aged 49.1±14.1 years, diagnosed with insulinoma in a Neuroendocrine Tumours centre between 2000 and 2014 were retrospectively reviewed. Prolonged (72-h) supervised fast was used for diagnosis (plasma glucose <40 mg/dl with simultaneous insulin level >6 μIU/ml). For tumour localisation, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasonography and intra-operative ultrasonography were performed.
Results: Sporadic insulinomas were diagnosed in 23 patients (92%); two insulinomas developed in patients with multiple endocrine neoplasia type 1 (8%). Hepatic metastases were present in two patients (8%). Median duration between the onset of hypoglycaemic symptoms and diagnosis was 2 years. Glucose nadir during 72-h fast was 30.9±7.1 mg/dl, with simultaneous median insulinaemia of 28 μIU/ml (25th percentile:15.2, 75th percentile:67.2 μIU/ml); mean C peptide during hypoglycaemia was 2.6±1.8 ng/ml. Median duration to nadir glucose was 8 h (25th percentile:4.25, 75th percentile:12.25 h). Abdominal CT localized the insulinoma in 21 patients (84%) of patients. Mean tumour diameters were 22.3±14.3 mm. Tumours localisation was: cephalic (n=7), uncinate process (n=2), pancreatic neck (n=3), pancreatic body (n=4), pancreatic tail (n=5). From 20 patients underwent surgery (enucleation/cephalic duodenopancreatectomy/distal pancreatectomy), 16 patients were cured (80%); two patients refused surgery, in one patient surgery was contraindicated due to severe cardiac comorbidities and two patients were lost from follow-up. Medical treatment with diazoxide (200300 mg/day) or somatostatin analogues were used in non-cured patients to control hypoglycaemia.
Conclusion: Partial pancreatectomy or enucleation provided a good cure rate in patients with pre-operative localised insulinomas.