Islet hyperplasia in adults: challenge to preoperatively diagnose non-insulinoma pancreatogenic hypoglycemia syndrome

World J Surg. 2006 May;30(5):670-9. doi: 10.1007/s00268-005-0543-6.

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.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Blood Glucose / analysis
  • Diagnosis, Differential
  • Female
  • Glucose Tolerance Test
  • Humans
  • Hyperplasia / complications
  • Hypoglycemia / diagnosis
  • Hypoglycemia / etiology*
  • Insulinoma / diagnosis
  • Islets of Langerhans / pathology*
  • Male
  • Middle Aged
  • Pancreatic Diseases / complications
  • Pancreatic Diseases / diagnosis*
  • Pancreatic Neoplasms / diagnosis

Substances

  • Blood Glucose