A gastrin-producing neuroendocrine tumor that arises from the duodenum. It is characterized by the presence of uniform cells that form pseudorosettes. The neoplastic cells have uniform nuclei and small amount of eosinophilic cytoplasm. The disease is Monarch Disease Ontology id MONDO_0004411 (duodenal gastrin-producing neuroendocrine tumor). Also known as: duodenal G-cell gastrin producing tumor, duodenal G-cell gastrin producing tumour, duodenal gastrin-producing NET, duodenal gastrinoma, duodenum gastrin-producing neuroendocrine tumor, duodenum gastrin-producing neuroendocrine tumour, gastrin producing tumor of duodenum, gastrin producing tumor of the duodenum.