Somatostatinoma

Review
In: Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000.
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Excerpt

Somatostatin-secreting tumors, or somatostatinomas represent less than 1% of functioning gastrointestinal neuroendocrine neoplasms (NENs) 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. Tumors that demonstrate D-cell differentiation based on immunohistochemical labelling with somatostatin but lack symptoms of somatostatinoma syndrome, such as those observed within the ampulla and duodenum, should be designated as somatostatin-producing well-differentiated NENs and are not considered somatostatinomas. Hereditary pancreatic somatostatin-producing well-differentiated NENs can be found as part of multiple neuroendocrine neoplasia type 1 (MEN1) and von-Hippel Lindau (VHL) syndrome, whereas duodenal (peri-ampullary somatostatin-producing NENs can be found in patients with neurofibromatosis type 1 (NF1). The polycythemia-paraganglioma-somatostatinoma syndrome is a rare syndrome including multiple paragangliomas, duodenal somatostatin-producing NENs (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 ultrasound (EUS) 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.

Publication types

  • Review