An insulinoma is a tumor of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumor. Most insulinomas are benign in that they grow exclusively at their origin within the pancreas, but a minority metastasize. Insulinomas are one of the functional PanNET group ("functional" because it increases production of insulin; "PanNET" as an abbreviation of pancreatic neuroendocrine tumor). In the Medical Subject Headings classification, insulinoma is the only sub-type of "islet cell adenoma".
Beta cells secrete insulin in response to increases in blood glucose. The resulting increase in insulin acts to lower blood glucose back to normal levels at which point further secretion of insulin is stopped. In contrast, the secretion of insulin by insulinomas is not properly regulated by glucose and the tumors will continue to secrete insulin causing glucose levels to fall further than normal.
As a result, patients present symptoms of low blood glucose (hypoglycemia), which are improved by eating. The diagnosis of an insulinoma is usually made biochemically with low blood glucose, elevated insulin, proinsulin and C-peptide levels and confirmed by localizing the tumor with medical imaging or angiography. The definitive treatment is surgery.
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https://www.hindawi.com/journals/jdr/2012/460869/ p. Dames, m. Weise, r. Puff, et al., “suppression of the nuclear factor eny2 increases insulin secretion in poorly functioning ins-1e insulinoma cells,” experimental diabetes research, vol. 2012, article id 460869, 8 pages, 2012. Doi:10.1155/2012/460869
https://www.hindawi.com/journals/omcl/2016/2594703/ han sung kim, tae-young han, and yeong-min yoo, “melatonin-mediated intracellular insulin during 2-deoxy-d-glucose treatment is reduced through autophagy and edc3 protein in insulinoma ins-1e cells,”oxidative medicine and cellular longevity, vol. 2016, article id 2594703, 11 pages, 2016. Doi:10.1155/2016/2594703
Arunraj s t, damle na, bal c, gupta y, pal s. Insulinoma - the incremental value of somatostatin receptor positron emission tomography. Indian j endocr metab [serial online] 2017 [cited 2017 jan 2];21:255-6. Available from: http://www.ijem.in/text.asp?2017/21/1/255/196025
https://www.hindawi.com/journals/cris/2015/375124/ ersin borazan, alper aytekin, latif yilmaz, et al., “multifocal insulinoma in pancreas and effect of intraoperative ultrasonography,” case reports in surgery, vol. 2015, article id 375124, 4 pages, 2015. Doi:10.1155/2015/375124
https://www.hindawi.com/journals/crie/2012/168671/ a. Janez, “insulinoma causing liver metastases 15 years after initial surgery, accompanied by glomerulonephritis,” case reports in endocrinology, vol. 2012, article id 168671, 3 pages, 2012. Doi:10.1155/2012/168671
https://www.hindawi.com/journals/crie/2013/636175/ emre bozkirli, okan bakiner, huseyin abali, et al., “a case of inoperable malignant insulinoma with resistant hypoglycemia who experienced the most significant clinical improvement with everolimus,” case reports in endocrinology, vol. 2013, article id 636175, 6 pages, 2013. Doi:10.1155/2013/636175