In: Endotext [Internet]. South Dartmouth (MA):, Inc.; 2000–.


Somatostatin-secreting tumors or somatostatinomas represent about 4% of gastrointestinal neuroendocrine neoplasms and their estimated incidence is about 1 in 40 million individuals per year. The spectrum of the somatostatinoma syndrome consists of diabetes mellitus, diarrhea/steatorrhea, cholelithiasis, hypochlorhydria, and weight loss. Hereditary pancreatic somatostatinomas can be found as part of multiple neuroendocrine neoplasia type 1 (MEN1) and von-Hippel Lindau (VHL) syndrome, whereas duodenal (peri-ampullary somatostatinomas can be found in patients with neurofibromatosis type 1 (NF1). The polycythemia-paraganglioma-somatostatinoma syndrome is a rare syndrome including multiple paragangliomas, duodenal somatostatinomas (exclusively found at the ampulla of Vater) associated with high erythropoietin (polycythemia) underlying paraganglioma/pheochromocytoma. The diagnosis of a somatostatinoma requires measuring fasting plasma somatostatin hormone concentration. A 3-phase CT, MRI, positron emission tomography (PET)-CT with gallium-labelled somatostatin analogs, or endoscopic ultrasonography should be performed for the precise localization of somatostatinomas in the pancreas or duodenum. A biopsy or surgical resection is required for grading (Ki67 index) and immunohistochemistry for somatostatin expression on tumor samples. Management of somatostatinomas includes medical treatment of the excess somatostatin production, surgical and/or radiological interventions, peptide receptor radiotherapy, and targeted or cytotoxic therapies. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.

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