Insulinoma is defined as a neuroendocrine tumor associated with clinical symptoms and biological alterations due to hyperinsulinism. It is a rare tumor but is the most frequent of functioning neuroendocrine tumors of the pancreas. Most insulinomas are small, circumscribed, and well-differentiated neoplasms. Their histological grade is usually G1. Some of them are associated with amyloid deposits in the stroma: this aspect is suggestive but not pathognomonic. Most, but not all, insulinomas express insulin and proinsulin detectable by immunohistochemistry. Insulinoma is the most frequent pancreatic tumor observed in the MEN-1 syndrome; some rare cases have also been described in neurofibromatosis type 1 and in tuberous sclerosis. In contrast, sporadic insulinomas exceptionally harbor mutations in MEN1 gene or in other genes known to be mutated in sporadic nonfunctioning pancreatic neuroendocrine tumors. Recently, a recurrent mutation in YY1 gene has been described in a significant proportion of sporadic insulinomas. More than 90 % of insulinomas behave as benign tumors; malignant insulinomas are defined by the presence of local invasion and/or metastatic dissemination
CITATION STYLE
Scoazec, J. Y. (2015). Insulinoma. In Pancreatic Neuroendocrine Neoplasms: Practical Approach to Diagnosis, Classification, and Therapy (pp. 75–80). Springer International Publishing. https://doi.org/10.1007/978-3-319-17235-4_8
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