A Duodenal Gastrinoma in a Patient with Diarrhea and Normal Serum Gastrin Concentrations

The Zollinger–Ellison syndrome manifests itself in 90 to 95 percent of cases as severe peptic ulcer disease.1 About half the time, the ulcer disease is associated with diarrhea, and in approximately 10 percent of patients, diarrhea is the only clinical manifestation.2,3 Basal serum gastrin concentrations are usually elevated in patients with this syndrome.4 Normal basal serum gastrin values with abnormal results of secretin tests have been reported, however, in a few patients.5–7 We describe a patient with a duodenal gastrinoma, a two-year history of diarrhea, and no peptic ulcer disease. The patient had persistently normal serum gastrin concentrations, . . .