[A young man with chronic diarrhea and epigastric pain].

CASE REPORT: A 26-year-old man was admitted to hospital with a 6-month history of diarrhea and abdominal pain. Before admission, upper and lower gastrointestinal endoscopy had shown a mild erosive duodenitis and the patient was started on a proton pump inhibitor. Physical examination and laboratory tests on admission were not constructive. In addition, repeated gastrointestinal endoscopy, cross-sectional imaging and neuroendocrine markers did not point to a specific etiology. Therefore, as a provocation test, the proton pump inhibitor therapy was discontinued. Discontinuation resulted in a progression of the patient's symptoms and an endoscopic detection of duodenal ulcers. Except for the normal serum gastrin levels, this constellation was suggestive of a gastrinoma, so that further investigations were initiated. Subsequently, the diagnosis could be confirmed and the gastrinoma located. After successful pancreaticoduodenectomy, the patient was symptom-free.

CONCLUSION: As part of a systematic investigation on chronic diarrhea, the work-up for neuroendocrine causes can play an important role. In this context, it should be kept in mind that some gastrinoma patients present without an elevation of serum gastrin levels. Regardless of a negative gastrin test, a typical symptom constellation should therefore prompt further investigations.