Nesidioblastosis Associated with Pancreatic Heterotopia as a Differential Diagnosis of Hypoglycemia: A Literature Review and Case Report

Patient: Male, 32-year-old Final Diagnosis: Nesidioblastosis Symptoms: Hypoglycemia Medication:— Clinical Procedure: Distal pancreatectomy • magnetic resonance image • selective arterial calcium stimulation test with hepatic venous sampling Specialty: Endocrinology and Metabolic OBJECTIVE: Rare co-existance of disease or pathology BACKGROUND: Nesidioblastosis is a rare disease that is part of the differential diagnosis of pancreatogenic hyperinsulinemic hypoglycemia (PHH) in patients whose imaging studies do not localize insulinoma. Pancreatic heterotopia is a rare congenital abnormality characterized by pancreatic tissue anatomically separated from the main gland and found in 0.5% of abdominal surgeries. The purpose of this article is to provide a systematic review of the literature on nesidioblastosis in pancreatic ectopic tissue and to describe a case of the co-occurrence of these 2 rare conditions. CASE REPORT: A 32-year-old man presented with adrenergic and neuroglycopenic symptoms, with laboratory-confirmed hyper-insulinemic hypoglycemia. There was no evidence of tumors on abdominal CT scan and MRI. Celiac trunk sampling with a calcium stimulation test was done, which showed an insulin gradient in the gastroduodenal artery. However, the intraoperative ultrasound showed a small nodule located at the pancreatic tail, leading to distal pancreatectomy. The histologic examination showed nesidioblastosis associated with pancreatic heterotopia. The patient remained asymptomatic after distal pancreatectomy. CONCLUSIONS: Nesidioblastosis accounts for 0.5%–5% of all cases of PHH, with a histology showing hypertrophy and hyper-plasia of pancreatic islets. Pancreatic heterotopia is a rare congenital anomaly resulting from failure of pancreatic cell migration, and is found as an incidentaloma in imaging or surgeries. Although it is a rare disease, nesidioblastosis should be considered in the investigation of hypoglycemia, even in the rare presentation of nesidioblastosis in patients with pancreatic heterotopy.