Hyperinsulinemic hypoglycemia associated with ectopic Cushing's syndrome due to a pancreatic endocrine tumor in a Type 2 diabetes mellitus patient: clinical implications of a rare association

J Endocrinol Invest. 2011 Mar;34(3):175-9. doi: 10.1007/BF03347062. Epub 2010 Apr 12.

Abstract

Background: The coexistence of insulin and ACTH hypersecretion in the same patient is extremely rare. A diabetic patient with a pancreatic endocrine tumor (PET) co-secreting insulin and ACTH is even rarer and has never been described. The combination of these two endocrine syndromes results in a peculiar clinical picture.

Aim: To determine the cause of glycemic variations in a patient with previously stable diabetes mellitus.

Subjects and methods: This is a clinical case report from the Endocrinology Unit of Aosta Hospital and Internal Medicine and Surgical Unit of Verona University. A 69-yr-old diabetic patient was hospitalized for recurrent severe hypoglycemic events persistent after withdrawal of anti-diabetic drugs. The causes of hypoglycemia and subsequent resumption of hyperglycemia were investigated.

Results: An insulin-secreting PET was diagnosed. Diazoxide and octreotide therapy initially was able to control hypoglycemic symptoms, then, a Cushing's syndrome occurred resulting in worsening of diabetes control. ACTH was found to be released by the PET previously diagnosed as an insulin-secreting tumor. The tumor was removed and the histology was consistent with a well differentiated endocrine carcinoma. After surgery, adrenal function was normal and insulin therapy was again necessary to control diabetes.

Conclusions: A single PET may be responsible for both a hyperinsulinemic and a Cushing's syndrome. When this rare association occurs, each of the two syndromes may affect the other resulting in a peculiar clinical course. Finally, an insulin-secreting PET has to be kept in mind as a rare cause of hypoglycemia in diabetic patients.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ACTH Syndrome, Ectopic / etiology*
  • ACTH Syndrome, Ectopic / pathology
  • ACTH Syndrome, Ectopic / surgery
  • Aged
  • Cushing Syndrome / complications*
  • Cushing Syndrome / etiology*
  • Cushing Syndrome / surgery
  • Diabetes Mellitus, Type 2 / complications*
  • Humans
  • Hyperinsulinism / etiology*
  • Hypoglycemia / etiology*
  • Insulinoma / complications*
  • Insulinoma / pathology
  • Insulinoma / surgery
  • Male
  • Pancreatic Neoplasms / complications*
  • Pancreatic Neoplasms / pathology
  • Pancreatic Neoplasms / surgery
  • Treatment Outcome