To eat, or not to eat… dietary patterns and the clinical recognition of insulinoma: a case report.

OBJECTIVES: Insulinoma is a rare pancreatic neuroendocrine tumor causing endogenous hyperinsulinemic hypoglycemia. Its heterogeneous clinical presentation often delays diagnosis. Dietary patterns, particularly ketogenic or high-carbohydrate regimens, may influence glucose homeostasis and modify the clinical manifestations of insulinoma. CASE PRESENTATION: A 70-year-old woman was admitted with recurrent documented hypoglycemia. She reported a 10-year history of seizure-like episodes and intermittent neurological symptoms that began after starting a ketogenic diet. Symptoms later became less frequent during a high-calorie, carbohydrate-rich diet but recurred after adopting a Mediterranean diet. Biochemical evaluation confirmed endogenous hyperinsulinemic hypoglycemia. A supervised fasting test documented symptomatic hypoglycemia with plasma glucose of 17 mg/dL, fulfilling Whipple's triad. Magnetic resonance imaging revealed a 4 cm pancreatic tail lesion, and ˆ68 Ga-DOTATATE PET/CT showed intense uptake consistent with a somatostatin receptor-positive neuroendocrine tumor. As the patient declined surgery, diazoxide and dietary modifications were started, improving symptoms and glycemic control. CONCLUSIONS: This case suggests that dietary habits may influence the clinical presentation of insulinoma. Marked carbohydrate restriction may unmask hypoglycemia, whereas high-carbohydrate intake may attenuate symptoms and contribute to delayed diagnosis. Careful assessment of dietary habits should be part of the evaluation of patients with recurrent unexplained hypoglycemia suggestive of insulinoma.