Adult-onset nesidioblastosis causing hypoglycemia: an important clinical entity and continuing treatment dilemma.

HYPOTHESIS Nesidioblastosis is an important cause of adult hyperinsulinemic hypoglycemia, and control of this disorder can often be obtained with a 70% distal pancreatectomy. DESIGN The records of all adult patients operated on for hypoglycemia between 1974 and 1999 were reviewed retrospectively. Patients with the pathologic diagnosis of nesidioblastosis were contacted for follow-up (1.5-21 years) and are presented. Patients' results were compared with those of 36 other individuals with this disorder who were previously reported in the literature. SETTING The University of Chicago Medical Center (Chicago, Ill), a tertiary care facility. PATIENTS A consecutive sample of all patients operated on for hypoglycemia. INTERVENTIONS Seventy percent distal pancreatectomy for all patients with nesidioblastosis, and maintenance therapy with verapamil hydrochloride for 2 patients. MAIN OUTCOME MEASURES Achievement of normoglycemia with and without medication, development of insulin-dependent diabetes mellitus, pancreatic exocrine insufficiency, and need for reoperation. RESULTS Of 32 adult patients who underwent surgical exploration for hyperinsulinemic hypoglycemia at our institution, 27 (84%) were found to have 1 or more insulinomas, and 5 (16%) were diagnosed with nesidioblastosis. Each patient with nesidioblastosis underwent a 70% distal pancreatectomy. Follow-up duration for the 5 patients ranged from 1.5 to 21 years, with 3 patients (60%) asymptomatic and taking no medications, and 2 patients (40%) experiencing some recurrences of hypoglycemia. The 2 patients with recurrences are now successfully treated with a calcium channel blocker, an approach, to our knowledge, never before reported for adult-onset nesidioblastosis. CONCLUSIONS Nesidioblastosis is an uncommon but clinically important cause of hypoglycemia in the adult population, and must always be considered in a patient with a presumptive preoperative diagnosis of insulinoma. This study indicates that a 70% distal pancreatectomy is often successful in controlling hypoglycemia, and rarely results in diabetes mellitus. However, the optimal treatment of this disorder remains to be determined.