Duodenal gastrinoma - case report

In our text, we want to highlight a rare diagnosis.

A 54-year-old obese, hypertensive male smoker had been investigated for intermittent abdominal pain for 12 years. The first gastroscopy for a bleeding ulcer was conducted in 2010. In the subsequent years, repeated gastroscopies revealed variable involvement from the esophagus to the duodenum. Capsule enteroscopy did not provide further specification of the diagnosis. The patient underwent colonoscopy and MRI enterography multiple times, with no unequivocal pathological findings. In May 2022, he was admitted to our department for abdominal pain and vomiting. This time, gastroscopy revealed multiple small ulcers in the duodenum and jejunum with clots causing a mechanical obstruction. Chromogranin A was elevated, raising suspicion of gastrinoma. However, somatostatin receptor-based imaging (Octreoscan) was negative. Only the 68Ga-DOTATOC PET (positron emission tomography with the radiopharmaceutical DOTA, labeled with gallium-68) identified a lesion in the subhepatic region, which had no correlation on CT. We concluded the diagnosis as gastrinoma with the Zollinger-Ellison syndrome. Endoscopically, a 1cm tumor was found in the duodenum. In October 2022, the patient underwent an excision of the duodenal wall, and the pathology assessment confirmed our diagnosis of gastrinoma.

With this case report, we want to emphasize the importance of taking into account neuroendocrine tumors in our differential diagnostic considerations. At the same time, we want to highlight that, according to ESMO recommendations, we should preferentially use 68Ga-DOTATOC PET/CT for the diagnosis instead of scintigraphic examination (111In-Octreoscan).