Endocrine Abstracts

Introduction: The non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS) identifies a group of hyperinsulinemic hypoglycemic patients with unique clinical, diagnostic, surgical, and pathologic features. A selective arterial calcium stimulation test (SACST) with hepatic venous sampling can be performed to distinguish between a focal abnormality (insulinoma) and a diffuse process (islet-cell hypertrophy/nesidioblastosis). In patients with insulinoma, the response is positive in one artery alone unless the tumor resides in a “watershed” area fed by two arteries or the patient has multiple insulinomas scattered throughout the pancreas. In contrast, in patients with islet-cell hypertrophy, positive responses are usually but not always observed after injection of multiple arteries.

Case: A 50-year-old female previously had a parathyroid surgery and total gastrectomy; pathology revealed gastric neuroendocrine tumor (G-NET). The diagnosis was multiple endocrine neoplasia type 1 (MEN-1). She was admitted to our hospital for hypoglycemia. Her low fasting plasma glucose level (22 mg/dl), high insulin level (8.4 μU/ml), c-peptide level (2.3 ng/ml) were consistent with the possible presence of insulinoma. But an abdominal CT revealed no pancreatic tumor, and angiography of splenic artery showed no definite tumor stain within the pancreas, negative endoscopic ultrasound, negative octreotide scan and negative ¹⁸F-DOPA PET. SACST was performed due to negative noninvasive imaging. Arterial stimulation and venous sampling showed an abnormal insulin response from superior mesenteric, gastroduodenal and splenic artery. The final diagnosis was adult-onset nesidioblastosis. The long-term therapeutic approaches for persistent hyperinsulinemic hypoglycemia may be accomplished pharmacologically or surgically. Pharmacologic interventions, although frequently unsuccessful, always should be tried before surgery. However, our case treatment with diazoxide at a starting dose of 200 mg/day dosage was gradually increased finally dose 400 mg/day resulted in amelioration hypoglycemia.

Discussion: Nesidioblastosis is a condition that can be seen in the majority of MEN1 patients with pancreatic involvement. Endogenous hyperinsulinemia may be due to single or more insulinoma, or it may also be due to diffuse hyperplasia, as seen in our case. The primary goal of therapy in nesidioblastosis is the prevention of acute neurologic symptoms (eg, seizure, lethargy, coma) and long-term sequelae (eg, cognitive deficits) of prolonged and/or recurrent hypoglycemia. The therapeutic strategies in nesidioblastosis include pancreatectomy and /or medical treatment. The initial treatment consists of nutritional management and use of diazoxide. This case report suggests that diazoxide may be effective for nesidioblastosis with MEN1 syndrome.