{"id":4422500,"date":"2025-01-11T21:30:54","date_gmt":"2025-01-12T03:30:54","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/topics\/insulinoma\/"},"modified":"2025-01-12T12:38:46","modified_gmt":"2025-01-12T18:38:46","slug":"insulinoma","status":"publish","type":"oen_topic","link":"https:\/\/myendoconsult.com\/learn\/topics\/insulinoma\/","title":{"rendered":"Insulinoma"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">INSULINOMA<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Cause of Endogenous Hyperinsulinemic Hypoglycemia<\/strong>\n<ul class=\"wp-block-list\">\n<li>Most common when a neoplasm of pancreatic \u03b2-cells <strong>(insulinoma)<\/strong> inappropriately secretes insulin.<\/li>\n\n\n\n<li>Incidence: <strong>4 cases per 1,000,000 people per year<\/strong>.<\/li>\n\n\n\n<li>Typically benign (\u223c95%) and <strong>sporadic (\u223c95%)<\/strong>.<\/li>\n\n\n\n<li><strong>Malignant:<\/strong> \u223c5%.<\/li>\n\n\n\n<li><strong>Association with MEN1:<\/strong> \u223c5% of insulinomas occur in multiple endocrine neoplasia type 1 (MEN1).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Tumor Characteristics<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Usually solitary<\/strong> (\u223c85%).<\/li>\n\n\n\n<li><strong>Multiple tumors<\/strong> in \u223c10% of cases (more common in MEN1).<\/li>\n\n\n\n<li><strong>Malignant<\/strong> in \u223c5%.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Pathophysiology<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Insulin secretion fails to decrease<\/strong> as plasma glucose concentrations fall.<\/li>\n\n\n\n<li><strong>Primary mechanism of hypoglycemia:<\/strong> insulin-induced decrease in hepatic glucose output in the fasting state.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"2250\" height=\"1875\" src=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells.png\" alt=\"\" class=\"wp-image-4422746\" srcset=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells.png 2250w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells-300x250.png 300w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells-768x640.png 768w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells-1536x1280.png 1536w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/islet-cells-2048x1707.png 2048w\" sizes=\"auto, (max-width: 2250px) 100vw, 2250px\" \/><figcaption class=\"wp-element-caption\">Types of pancreatic cells<\/figcaption><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">CLINICAL PRESENTATION<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Episodic Hypoglycemia<\/strong> with:\n<ol class=\"wp-block-list\">\n<li><strong>Neuroglycopenic symptoms<\/strong>\n<ul class=\"wp-block-list\">\n<li>Visual changes<\/li>\n\n\n\n<li>Confusion<\/li>\n\n\n\n<li>Unusual behavior<\/li>\n\n\n\n<li>Possible unconsciousness or seizures if severe<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Sympathoadrenal symptoms<\/strong>\n<ul class=\"wp-block-list\">\n<li>Tremulousness<\/li>\n\n\n\n<li>Sweating<\/li>\n\n\n\n<li>Palpitations<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/whipple-triad\/\" data-wpil-monitor-id=\"245\">Whipple\u2019s Triad<\/a><\/strong> (classic criteria for endogenous hypoglycemia):\n<ol class=\"wp-block-list\">\n<li><strong>Symptoms consistent with hypoglycemia<\/strong> (neuroglycopenia + sympathetic overactivity).<\/li>\n\n\n\n<li><strong>Documented low plasma glucose<\/strong> (&lt;45 mg\/dL in venous plasma).<\/li>\n\n\n\n<li><strong>Relief of symptoms<\/strong> when glucose is administered.<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">DIAGNOSIS<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Biochemical Testing<\/strong>\n<ul class=\"wp-block-list\">\n<li>Demonstrate <strong>low plasma glucose<\/strong> (e.g., &lt;45 mg\/dL) <strong>with<\/strong> inappropriately increased levels of:\n<ul class=\"wp-block-list\">\n<li><strong>Insulin<\/strong><\/li>\n\n\n\n<li><strong>C-peptide<\/strong><\/li>\n\n\n\n<li><strong>Proinsulin<\/strong><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u03b2-hydroxybutyrate<\/strong>: <strong>low<\/strong> (&lt;2.7 mmol\/L) because of <a href=\"https:\/\/myendoconsult.com\/learn\/physiological-effects-of-insulin\/\" data-wpil-monitor-id=\"246\">insulin\u2019s antilipolytic effect<\/a>.<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/glucagon-stimulation-test\/\" data-wpil-monitor-id=\"247\">Glucagon stimulation<\/a> at end of fast<\/strong>: a rise in plasma glucose &gt;25 mg\/dL (within 30 min) suggests insulinoma (retained glycogen in liver due to hyperinsulinemia).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Fasting Tests<\/strong>\n<ul class=\"wp-block-list\">\n<li>Most insulinoma patients become hypoglycemic within <strong>48 hours<\/strong> of a supervised fast.<\/li>\n\n\n\n<li>Some require a <strong>72-hour fast<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Sulfonylurea Screening<\/strong>\n<ul class=\"wp-block-list\">\n<li>Measure drugs that stimulate insulin release (e.g., sulfonylureas, repaglinide, nateglinide).<\/li>\n\n\n\n<li>Exclude factitious hypoglycemia from exogenous secretagogues or insulin.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Differential Diagnosis<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Pancreatic \u03b2-cell hyperplasia<\/strong> (nesidioblastosis).<\/li>\n\n\n\n<li><strong>Insulin autoimmune hypoglycemia<\/strong>.<\/li>\n\n\n\n<li><strong>Medications<\/strong>: exogenous insulin, oral insulin secretagogues (sulfonylureas).<\/li>\n\n\n\n<li><strong>Critical illness<\/strong>: hepatic\/renal failure, sepsis.<\/li>\n\n\n\n<li><strong>Counterregulatory hormone deficiency<\/strong>: Addison disease.<\/li>\n\n\n\n<li><strong>Non-islet cell tumor hypoglycemia<\/strong> (large mesenchymal tumors).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">LOCALIZATION STUDIES<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Tumor Size<\/strong>: Often very small (40% &lt;1.0 cm).<\/li>\n\n\n\n<li><strong>Imaging Approaches<\/strong>:\n<ol class=\"wp-block-list\">\n<li><strong>Contrast-enhanced CT<\/strong> of the pancreas: detects \u223c75% of insulinomas.<\/li>\n\n\n\n<li><strong>Ultrasonography<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Transabdominal<\/strong><\/li>\n\n\n\n<li><strong>Endoscopic<\/strong> (sensitivity up to 90%).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Selective Arterial Calcium Stimulation<\/strong> with hepatic venous sampling (for regionalizing tumor to a part of the pancreas).<\/li>\n\n\n\n<li><strong>Intraoperative Pancreatic Ultrasound<\/strong>: confirmatory localization during surgery.<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">TREATMENT<\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"3263\" height=\"2175\" src=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment.png\" alt=\"\" class=\"wp-image-4422744\" srcset=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment.png 3263w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment-300x200.png 300w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment-768x512.png 768w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment-1536x1024.png 1536w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/insulinoma-treatment-2048x1365.png 2048w\" sizes=\"auto, (max-width: 3263px) 100vw, 3263px\" \/><figcaption class=\"wp-element-caption\">Treatment options for insulinoma<\/figcaption><\/figure>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgical Resection<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Best definitive therapy<\/strong> if complete removal is feasible.<\/li>\n\n\n\n<li><strong>Enucleation<\/strong> of solitary tumor if possible, sparing normal pancreas.<\/li>\n\n\n\n<li><strong>Partial pancreatectomy<\/strong> may be required if enucleation not feasible.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Special Cases<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Tumor in <strong>pancreatic head<\/strong> and cannot be enucleated: <strong>Whipple procedure<\/strong> (pancreaticoduodenectomy + duodenectomy + partial gastrectomy + splenectomy).<\/li>\n\n\n\n<li><strong>Malignant insulinoma<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Remove as much tumor as possible.<\/li>\n\n\n\n<li><strong>Metastases<\/strong> commonly in the liver.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Management of Metastatic or Unresectable Disease<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Ablative therapies<\/strong>: hepatic artery embolization, radiofrequency ablation, cryoablation, or ethanol ablation under endoscopic ultrasound guidance.<\/li>\n\n\n\n<li><strong>Medications<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Diazoxide (suppresses insulin release).<\/li>\n\n\n\n<li>Octreotide (somatostatin analogue).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Chemotherapy<\/strong> (e.g., streptozocin-based) for advanced disease.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>INSULINOMA Tumor Characteristics Pathophysiology CLINICAL PRESENTATION DIAGNOSIS LOCALIZATION STUDIES TREATMENT<\/p>\n","protected":false},"featured_media":0,"template":"","oen_topic_chapter":[686],"class_list":["post-4422500","oen_topic","type-oen_topic","status-publish","hentry","oen_topic_chapter-the-pancreas","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422500","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/oen_topic"}],"version-history":[{"count":5,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422500\/revisions"}],"predecessor-version":[{"id":4422748,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422500\/revisions\/4422748"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=4422500"}],"wp:term":[{"taxonomy":"oen_topic_chapter","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic_chapter?post=4422500"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}