[Duodenal gastrinoma with the development of Zollinger-Ellison syndrome].

Gastrinoma consisting of eosinophilic gastrin--producing cells (this was proven electron--microscopically and immunohistochemically) was found in a 32-year-old female. The tumour, 1 x 1 x 1.5 cm in size, was located in the submucosa of the horizontal part of the duodenum. This was the cause of Zollinger--Ellison syndrome in the above patient.