Multiple Endocrine Neoplasia Type 1 (MEN1) Differential Diagnoses

Updated: Jan 05, 2022
  • Author: Catherine Anastasopoulou, MD, PhD, FACE; Chief Editor: George T Griffing, MD  more...
  • Print

Diagnostic Considerations

Hyperparathyroidism in multiple endocrine neoplasia type 1 (MEN1) must be separated from other familial forms of hypercalcemia, including familial parathyroid hyperplasia and familial adenomatous hyperparathyroidism. Familial hypocalciuric hypercalcemia may also have a similar presentation. These latter 2 syndromes have no pancreatic or pituitary manifestations.

Conditions other than Zollinger-Ellison syndrome (ZES) that are associated with elevated serum gastrin levels include the following:

  • Retained gastric antrum
  • Gastric outlet obstruction
  • Hypercalcemia
  • Massive small bowel resection
  • Atrophic gastritis
  • Proton pump inhibitor therapy

Patients with MEN1-associated ZES are on average 10 years younger than those with sporadic ZES at the time of diagnosis. ZES should be considered in MEN1 patients with new digestive symptoms, including loose stools, especially when diarrhea promptly disappears when using proton pump inhibitor (PPI) therapy, epigastric pain and signs of GERD without severe esophagitis or tiny duodenal erosions on gastroscopy.

Differential Diagnoses