Endocrine Abstracts

Clinical caseIntroduction: Insulinoma is a rare disorder with an estimated incidence of 1 case per 250 000 people per year.

Case report: 37 years old female, with a history of irritable bowel syndrome, dyslipidemia and kidney stones. In December 2010, she developed a headache, dizziness and visual disturbances, predominantly in the evening and amnesia for some of the episodes. Initially interpreted as peripheral vertiginous syndrome, because of recurrence of symptoms, interfering in daily activity, she developed psycho-emotional instability and anxiolytic medication was prescribed. In April she had a similar episode accompanied by syncope and imbalance, she was assisted at the Health Center with 31 mg/dl. She was admitted for hypoglycemic investigation. She performed a fasting test that was stopped an hour later through symptomatic hypoglycemia (serum glucose levels of 25 mg/dl, insulin 36.3 μU/ml, C-peptide 5.06 ng/ml), with increase of the serum glucose levels >25 mg/dl after glucagon, suggestive of endogenous hyperinsulinism. CT showed nodular mass in the pancreatic head with 21 mm with the arterial phase uptake suggestive of insulinoma without mesenteric or retroperitoneal lymphadenopathy. She underwent tumor enucleation\. Pathological examination showed well differentiated insulinoma 1.8×1.5×1.2 cm, low mitotic index, Ki 67 3%, with no necrosis and no vascular invasion or surgical margin, synaptophysin positive. After surgery she remains clinically well.

Discussion: This case illustrates the need for high clinical suspicion for insulinoma diagnosis. Neuroglycopenia and adrenergic symptoms are often confused with acute vertigo and anxiety disorders. Although it was the case with this patient, the delay in diagnosis was only five months. Some studies have shown average delays in diagnosis of 1.5 years. In this case, the patient has a tumor with good prognosis (pT1N0M0, stage IA), with an estimated survival at 5 years of 61%.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.