, Volume 30, Issue 5, pp 670-679
Date: 17 Mar 2006

Islet Hyperplasia in Adults: Challenge to Preoperatively Diagnose Non-Insulinoma Pancreatogenic Hypoglycemia Syndrome

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Abstract

Background

Pancreatic hyperfunctional islet hyperplasia in adults has been more and more frequently described in the literature. Postprandial neuroglycopenia, a negative normal fasting test, negative pancreatic imaging results, and positive intra-arterial calcium stimulation of serum insulin are characteristic. In affected patients the term non-insulinoma pancreatogenic hypoglycemia syndrome (NIPHS) was proposed.

Materials and Methods/Patients

We also encountered fasting hypoglycemia in such patients and therefore evaluated clinical and biochemical data in patients with NIPHS (n = 11), patients with insulinoma (n = 70), and patients in whom hypoglycemia was ruled out (n = 70).

Results

Patients with NIPHS were younger (median age: 41 years; range: 18–66) and mostly non-obese (median body mass index/BMI: 22.2 kg/m2; range: 19–39) compared with patients with an insulinoma (median age: 50 years; median: BMI 26.1 kg/m2). During an oral glucose tolerance test (OGTT) followed by a standard fasting test, neuroglycopenia was observed postprandially with a mean minimal blood glucose level of 36 ± 9 mg/dl in 7 out of 11 patients. Spontaneous hypoglycemia during the fast was 38 ± 5 mg/dl in 8 out of 11 patients. The corresponding insulin levels were 9.2 ± 9.8 mU/l (OGTT) and 6.8 ± 5.4 mU/l (fasting), significantly lower than in patients with insulinoma (P < 0.001), but not different from patients without hypoglycemia (P = 0.05). After pancreatic resection 8 patients (73%) were cured with enduring euglycemia. Pathohistological islet abnormalities with hyperplasia, hypertrophy, and microadenomatosis were confirmed in all patients.

Conclusion

In patients with postprandial and/or fasting neuroglycopenia NIPHS may be suspected when insulin levels are low but inadequately suppressed and localization studies failed to show a distinct pancreatic tumor.