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Where Are Insulinomas Found

Pancreatic Neuroendocrine Tumors: Insulinoma

Pancreatic Neuroendocrine Tumors: Insulinoma

What is an insulinoma? An insulinoma is a tumor, usually benign (non-cancerous), made up of specialized beta islet cells (see below) that constantly secrete insulin, causing hypoglycemia (low blood glucose–sugar). Normally, as the glucose rises with eating, the pancreas responds by secreting more insulin, which in turn helps utilize or store the glucose and its blood level drops back down into a safe range. Subsequently, as the glucose level continues to fall toward the lower limit of normal (normal, 60-100mg/dL), the secretion of insulin (by the normal beta cells in the pancreas) stops, and this allows the glucose to remain in the normal range. This type of feedback regulation is the hallmark of endocrine organs (thyroid, parathyroid, endocrine part of the pancreas, pituitary, gonad, and adrenal glands that secrete specific hormones). When an insulinoma is present, insulin regulation is abnormal such that the tumor continues to secrete insulin even though the glucose level may fall to a dangerously low level. Even though insulinoma is the most common pancreatic islet cell tumor, it is very rare, occurring in only 3-4 per million people. Except in very rare familial (occurring in families, transmitted genetically from parent to child) situations, the exact cause is unknown. Figure 1: The average age to develop an insulinoma is the mid-40s (range, 10-82 years), and occurs slightly more frequently in females than males. Most are sporadic (occurring "out of the blue" with no known cause) with about 10% occurring as part of the Multiple Endocrine Neoplasia type 1 (MEN 1) syndrome. At least 90% have single, benign, small (less than 2 cm – 3/4 of an inch) tumors (Figure 1). Hypoglycemic symptoms are experienced by virtually all patients with insulinoma and can be grouped Continue reading >>

Improved Control Of Severe Hypoglycemia In Patients With Malignant Insulinomas By Peptide Receptor Radionuclide Therapy

Improved Control Of Severe Hypoglycemia In Patients With Malignant Insulinomas By Peptide Receptor Radionuclide Therapy

The Journal of Clinical Endocrinology & Metabolism Improved Control of Severe Hypoglycemia in Patients with Malignant Insulinomas by Peptide Receptor Radionuclide Therapy Department of Internal Medicine, Section of Endocrinology (E.v.S., R.A.F., K.K., W.W.d.H.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments of Nuclear Medicine (E.I.v.V., E.P.K., S.K., R.V., J.J.M.T., D.J.K.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Department of Internal Medicine, Section of Endocrinology (E.v.S., R.A.F., K.K., W.W.d.H.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments of Nuclear Medicine (E.I.v.V., E.P.K., S.K., R.V., J.J.M.T., D.J.K.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments of Nuclear Medicine (E.I.v.V., E.P.K., S.K., R.V., J.J.M.T., D.J.K.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Department of Internal Medicine, Section of Endocrinology (E.v.S., R.A.F., K.K., W.W.d.H.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments of Nuclear Medicine (E.I.v.V., E.P.K., S.K., R.V., J.J.M.T., D.J.K.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Pathology (F.H.v.N.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments of Nuclear Medicine (E.I.v.V., E.P.K., S.K., R.V., J.J.M.T., D.J.K.), Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands Search for other works by this author on: Departments Continue reading >>

Preoperative Detection Of Pancreatic Insulinomas On Multiphasic Helical Ct

Preoperative Detection Of Pancreatic Insulinomas On Multiphasic Helical Ct

OBJECTIVE. The objective was to analyze enhancement characteristics of insulinomas and to determine the ability of multiphase CT to localize these tumors. MATERIALS AND METHODS. Prospective interpretations of multiphase helical CT scans were reviewed in 30 patients who had insulinomas resected over a 5-year period. CT scans were retrospectively reviewed to determine enhancement characteristics, tumor conspicuity in each phase of enhancement, and potential causes for false-negative findings. RESULTS. Sixty-three percent (19/30) of tumors were identified on CT prospectively. An additional six tumors were visualized in retrospect, allowing characterization of 25 (83%) of 30 tumors. Most tumors were hyperdense on at least one phase (n = 19), three tumors were hypoattenuating, and three were isodense and pedunculated. Insulinomas were most conspicuous on the early phase in 15 patients and in the portal venous phase in three. All tumors that underwent pancreatic phase imaging were seen (13/13), whereas three of 18 arterial and six of 25 portal venous phase findings were inconclusive for tumor. In the six examinations with false-negative findings in which the tumor could be seen in retrospect, two tumors were isodense and pedunculated, three were in close proximity to vessels, and one had a cystic appearance. CONCLUSION. Multiphasic CT has a moderate sensitivity in the detection of insulinomas. Most tumors are more conspicuous on the earlier phases of enhancement. The pancreatic phase may be more useful than the arterial phase. Potential sources of false-negative results include tumors adjacent to vessels, pedunculated morphology, or nonhyperattenuating lesions. Continue reading >>

Practice Essentials

Practice Essentials

Insulinomas are the most common cause of hypoglycemia resulting from endogenous hyperinsulinism. Approximately 90-95% of insulinomas are benign, and long-term cure with total resolution of preoperative symptoms is expected after complete resection. [1] See the image below. Signs and symptoms Insulinomas are characterized clinically by the Whipple triad, as follows: Presence of symptoms of hypoglycemia (about 85% of patients) Documented low blood sugar at the time of symptoms About 85% of patients with insulinoma present with one of the following symptoms of hypoglycemia: Hypoglycemia can also result in the following: Adrenergic symptoms (from hypoglycemia-related adrenalin release): Weakness, sweating, tachycardia, palpitations, and hunger See Clinical Presentation for more detail. Diagnosis Lab studies Failure of endogenous insulin secretion to be suppressed by hypoglycemia is the hallmark of an insulinoma. Thus, the finding of inappropriately elevated levels of insulin in the face of hypoglycemia is the key to diagnosis. The biochemical diagnosis of insulinoma is established in 95% of patients during prolonged fasting (up to 72 h) when the following results are found: Serum insulin levels of 10 µU/mL or more (normal < 6 µU/mL) C-peptide levels exceeding 2.5 ng/mL (normal < 2 ng/mL) Proinsulin levels greater than 25% (or up to 90%) of immunoreactive insulin levels Imaging studies Insulinomas can be located with the following imaging modalities: Real-time transabdominal high-resolution ultrasonography: 50% sensitivity Intraoperative transabdominal high-resolution ultrasonography with the transducer wrapped in a sterile rubber glove and passed over the exposed pancreatic surface: Detects more than 90% of insulinomas Computed tomography (CT) scanning: 82-94% sensitivity Continue reading >>

9 Insulinoma

9 Insulinoma

Although rare, insulinomas are the most common functioning islet cell tumour of the pancreas. Recognition of the key neuroglycopenic symptoms should trigger the initial investigation. Biochemical proof of endogenous hyperinsulinemic hypoglycemia establishes the diagnosis. Several options are available for imaging and localizing these tumours including ultrasonography, computed tomography, and intra-arterial calcium stimulation with venous sampling. The tumours are usually small, single, benign, well-circumscribed, and evenly distributed throughout the pancreas. This tumour may be a part of the multiple endocrine neoplasia type 1 (MEN-1) syndrome, in which case the tumours are almost always multiple. Surgical treatment is the only curative method, traditionally accomplished with enucleation or partial pancreatic resection. Patients are almost invariably cured lifelong with complete excision of a benign insulinoma. The most recent developments in this area are the recognition of noninsulinoma pancreatogenous hypoglycemia syndrome as a cause of organic hypoglycemia, and the development of laparoscopic techniques to excise these tumours. Continue reading >>

Insulinoma

Insulinoma

Causes, incidence, and risk factors: The pancreas is an organ in the abdomen. The pancreas makes several enzymes and hormones, including the hormone insulin. Insulin's job is to reduce the level of sugar (glucose) in the blood by helping it move into cells. Most of the time when your blood sugar level drops too low, the pancreas stops making insulin until your blood sugar returns to normal. Tumors of the pancreas that produce too much insulin are called insulinomas. Insulinomas keep making insulin, even when your blood sugar drops too low. A high blood insulin level causes a low blood sugar level (hypoglycemia ). Hypoglycemia may be mild, leading to symptoms such as anxiety and hunger. Or it can be severe, leading to seizures, coma, and even death. Insulinomas are rare tumors. They usually occur as single, small tumors in adults. These tumors are very rare in children. Most children with high blood insulin levels have many areas of overactive insulin-releasing cells in the pancreas, instead of a single tumor. More than 90% of insulinomas are non-cancerous (benign) tumors. People with the genetic syndrome called multiple endocrine neoplasia type I are at risk of insulinomas and other endocrine tumors . Symptoms: Behavior changes Clouded vision Coma Dizziness Headache Hunger Sweating Tremor Weight gain Signs and tests: After fasting, your blood may be tested for: Blood C-peptide level Blood glucose level Blood insulin level Drugs that cause the pancreas to release insulin CT or MRI scan of the abdomen , or PET scan may be done to look for a tumor in the pancreas. If the test is negative, one of the following tests may be performed: Treatment: Surgery is the recommended treatment for insulinoma. The tumor is first found by tests or surgery. Medication may be used to get pa Continue reading >>

Early-phase Thin-slice Ct In The Diagnosis Of Small Insulinomas

Early-phase Thin-slice Ct In The Diagnosis Of Small Insulinomas

Hideki Ishioka, Naohiro Sata, Yasunao Ishiguro, Alan Lefor, Yoshikazu Yasuda Department of Surgery, Jichi Medical University, Tochigi, Japan *Corresponding Author: Department of Surgery Jichi Medical University 3311-1 Yakushiji Shimotsuke Tochigi 329-0498, Japan Phone +81-285-58-7371 Fax +81-285-44-3234 E-mail [email protected] Visit for more related articles at JOP. Journal of the Pancreas Abstract Context Insulinomas, which are generally smaller than 2 cm, may be difficult to detect by routine imaging modalities including abdominal ultrasonography, computed tomography, and magnetic resonance imaging. Although preoperative detection of insulinomas is essential for operative planning, it is often challenging due to their small size. While arterial stimulation and venous sampling has been used in patients with insulinomas it has been largely supplanted by early-phase thin-slice computed tomography. Case report We report three patients with insulinomas, which were not detected by routine computed tomography scan, but were successfully imaged using early-phase thin-slice computed tomography. Enucleation was performed in all patients based on preoperative imaging. All three patients had an unremarkable postoperative course. Conclusion Early-phase thin-slice computed tomography is recommended for the preoperative identification of insulinomas. This non-invasive imaging technique should be considered before performing arterial stimulation and venous sampling. Continue reading >>

Localization Of Insulinomas

Localization Of Insulinomas

Hypothesis Intraoperative ultrasonography is more sensitive than preoperative and other intraoperative techniques for localizing insulinoma. Design Retrospective review. Setting A tertiary referral center. Patients All patients with a biochemical diagnosis of organic hyperinsulinism who were referred to University of California, San Francisco, from 1975 to 1998. Methods Sensitivities of the localization techniques for insulinoma were evaluated. Results The sensitivities of tumor localization with arteriography, computed tomography, preoperative ultrasonography, magnetic resonance imaging, magnetic resonance imaging with gadolinium, transhepatic venous sampling, palpation, and intraoperative ultrasonography were 47%, 24%, 50%, 30%, 40%, 55%, 76%, and 91%, respectively. Nine of the 11 nonpalpable and nonvisible tumors at operation were localized by intraoperative ultrasonography. Conclusion The currently available preoperative localization tests are not reliable enough to be recommended when intraoperative ultrasonography is available. A VARIETY of procedures have been advocated for detecting insulin-secreting tumors, but there is little consensus about the best method or combination of methods. After the diagnosis of insulinoma is established, most endocrinologists, surgeons, and patients would prefer preoperative localization if a reliable and cost-effective test were available. Selective arteriography was formerly used for preoperative localization of insulinoma but is usually no longer recommended because it only, at best, identifies about 60% of the tumors, and these are the larger tumors that the surgeon can usually easily identify. Arteriography is also invasive and expensive.1 Other localization studies have been used, including preoperative ultrasonography, trans Continue reading >>

Diagnosis And Management Of Insulinoma

Diagnosis And Management Of Insulinoma

Go to: CLINICAL SIGNS Insulinomas are the most common cause of hypoglycemia related to endogenous hyperinsulinism. The episodic nature of the hypoglycemic attack is due to the intermittent secretion of insulin by the tumor[8]. Common autonomic symptoms of an insulinoma include diaphroresis, tremor, and palpitations, whereas neuroglycopenenic symptoms include confusion, behavioral changes, personality changes, visual disturbances, seizures and coma[34,35]. Diagnosis of insulinomas can be challenging. Although it was originally considered that symptoms only became evident in the fasting state or following exercise, it is now known that patients with an insulinoma can also present with postprandial symptoms[36,37]. The classical diagnosis of insulinoma depends on satisfying the criteria of Whipple’s triad, which remains the cornerstone of the screening process: (1) hypoglycemia (plasma glucose < 50 mg/dL); (2) neuroglycopenic symptoms; and (3) prompt relief of symptoms following the administration of glucose (Table 1)[38]. In adults with symptoms of neuroglycopenia or documented low blood glucose levels, the gold standard for biochemical diagnosis remains measurement of plasma glucose, insulin, C-peptide, and proinsulin during a 72-h fast (Table 1). This prolonged fasting test can detect up to 99% of insulinomas[39]. Endogenous hypoglycemia due to insulinomas was previously based on findings of abnormal serum levels of insulin, C-peptide, and, more recently, proinsulin at the time of fasting hypoglycemia. To date, there is some general agreement regarding the diagnostic thresholds that must be reached for insulin, C-peptide, and proinsulin levels to be considered abnormal. Several years ago, ratios calculated from insulin and blood glucose levels were used, with the insu Continue reading >>

Insulinoma

Insulinoma

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).[1] In the Medical Subject Headings classification, insulinoma is the only subtype of "islet cell adenoma".[2] 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 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. Signs and symptoms[edit] Patients with insulinomas usually develop neuroglycopenic symptoms. These include recurrent headache, lethargy, diplopia, and blurred vision, particularly with exercise or fasting. Severe hypoglycemia may result in seizures, coma, and permanent neurological damage. Symptoms resulting from the catecholaminergic response to hypoglycemia (i.e. tremulousness, palpitations, tachycardia, sweating, hunger, anxiety, nausea) are not as common. Sudden weight gain is sometimes seen. Continue reading >>

Insulinoma

Insulinoma

What Is an Insulinoma? An insulinoma is a small tumor in the pancreas that produces an excess amount of insulin. In most cases, the tumor isn’t cancerous. Most insulinomas are less than 2 centimeters in diameter. The pancreas is an endocrine organ located behind your stomach. One of its functions is to produce hormones that control the level of sugar in your bloodstream, such as insulin. Normally, the pancreas stops creating insulin when your blood sugar drops too low. This allows your blood sugar levels to return to normal. When an insulinoma forms in your pancreas, however, it will continue to produce insulin, even when your blood sugar is too low. This can lead to severe hypoglycemia, or low blood sugar. Hypoglycemia is a dangerous condition that can cause blurred vision, lightheadedness, and unconsciousness. It can also be life-threatening. An insulinoma usually needs to be surgically removed. Once the tumor is removed, complete recovery is very likely. People with insulinomas don’t always have noticeable symptoms. When symptoms do occur, they can vary depending on the severity of the condition. Mild symptoms include: double vision or blurred vision confusion anxiety and irritability dizziness mood swings weakness sweating hunger tremors sudden weight gain More severe symptoms of insulinoma can affect the brain. They can also affect the adrenal glands, which regulate stress response and heart rate. Sometimes, symptoms seem similar to those of epilepsy, a neurological disorder that causes seizures. Symptoms that are seen in more serious cases of insulinoma may include: convulsions or seizures a rapid heart rate (greater than 95 beats per minute ) difficulty concentrating loss of consciousness or coma In some cases, insulinomas can get bigger and spread to other p Continue reading >>

Insulinoma

Insulinoma

The pancreas is an organ in the abdomen. The pancreas makes several enzymes and hormones, including the hormone insulin. Insulin's job is to reduce the level of sugar (glucose) in the blood by helping it move into cells. Most of the time when your blood sugar level drops too low, the pancreas stops making insulin until your blood sugar returns to normal. Tumors of the pancreas that produce too much insulin are called insulinomas. Insulinomas keep making insulin, even when your blood sugar drops too low. A high blood insulin level causes a low blood sugar level (hypoglycemia). Hypoglycemia may be mild, leading to symptoms such as anxiety and hunger. Or it can be severe, leading to seizures, coma, and even death. Insulinomas are rare tumors. They usually occur as single, small tumors. But there can also be several small tumors. Most insulinomas are non-cancerous (benign) tumors. People with certain genetic disorders such as multiple endocrine neoplasia type I are at risk for insulinomas. Continue reading >>

A-z Health Library

A-z Health Library

Insulinoma Definition: An insulinoma is a tumor in the pancreas that produces too much insulin. Causes, incidence, and risk factors: The pancreas is an organ in the abdomen. The pancreas makes several enzymes and hormones, including the hormone insulin. Insulin's job is to reduce the level of sugar (glucose) in the blood by helping it move into cells. Most of the time when your blood sugar level drops too low, the pancreas stops making insulin until your blood sugar returns to normal. Tumors of the pancreas that produce too much insulin are called insulinomas. Insulinomas keep making insulin, even when your blood sugar drops too low. A high blood insulin level causes a low blood sugar level (hypoglycemia ). Hypoglycemia may be mild, leading to symptoms such as anxiety and hunger. Or it can be severe, leading to seizures, coma, and even death. Insulinomas are rare tumors. They usually occur as single, small tumors in adults. These tumors are very rare in children. Most children with high blood insulin levels have many areas of overactive insulin-releasing cells in the pancreas, instead of a single tumor. More than 90% of insulinomas are non-cancerous (benign) tumors. People with the genetic syndrome called multiple endocrine neoplasia type I are at risk of insulinomas and other endocrine tumors . Symptoms: Behavior changes Clouded vision Coma Dizziness Headache Hunger Sweating Tremor Weight gain Signs and tests: After fasting, your blood may be tested for: CT or MRI scan of the abdomen , or PET scan may be done to look for a tumor in the pancreas. If the test is negative, one of the following tests may be performed: Continue reading >>

Insulinoma

Insulinoma

What is an insulinoma? The pancreas makes insulin, which helps keep your blood sugar level balanced. Tumors on your pancreas, called insulinomas, make extra insulin, more than your body can use. This causes blood sugar levels to drop too low. These tumors are rare and usually do not spread to other parts of your body. What causes an insulinoma? The cause of insulinomas is unknown. What are the risk factors for an insulinoma? There are few risk factors for insulinomas. But, women seem to be affected more often than men. Most often, it starts between ages 40 and 60. Some genetic diseases can raise your chance of getting an insulinoma. They are: Multiple endocrine neoplasia type 1, abnormal tissue growth in the endocrine system Von Hippel-Lindau syndrome, an inherited disease that causes tumors and cysts throughout your body Other genetic syndromes, such as neurofibromatosis type 1 and tuberous sclerosis What are the symptoms of an insulinoma? Insulinomas can cause these symptoms: Confusion Sweating Weakness Rapid heartbeat If your blood sugar gets too low, you can pass out and even go into a coma. How are insulinomas diagnosed? Insulinomas can be difficult to diagnose. The average time between the start of symptoms and a diagnosis is about 3 years. If your healthcare provider suspects an insulinoma, you may stay in the hospital for a few days. This is so your doctor can watch your blood sugar and other substances in your blood while you fast. You will not be able to eat or drink anything except water during this time. If you have an insulinoma, you will probably have very low blood sugar levels within 48 hours of starting this test. If your symptoms of low blood sugar have been after meals, you may also have a test of your blood sugar and insulin for several hours after a Continue reading >>

Diagnosis Difficulties In Insulinomas

Diagnosis Difficulties In Insulinomas

AE Ranetti, A Mazilu, C Spiroiu & A Mihai We have studied 5 cases of insulinomas presented in our clinic in 2004–2005 with typical signs and symptoms of hypoglycemia correlated with high insulinemia. The medium insulin value in the morning was 57.9 mUI/ml, but we found values ranging from 10–98 mUI/ml for medium and severe hypoglycemia. There was no correlation between severity of hypoglycemia and insulin level, proven by repeated insulin dosages. The purpose of our analysis was to identify the best-suitable diagnosis imaging methods for location of insulinomas, by comparing abdominal ultrasonography, CT, MRI and echographic endoscopy. None of the cases had shown positive results on abdominal (pancreatic) ultrasound. Four of the cases had negative abdominal CT scan, in one of this cases the tumor was identified on MRI abdominal scan, with 1.2 cm diameter, but all of them were visualized using echoendoscopy. The fifth case who underwent a previous unsuccessful pancreatic resection for insulinoma had negative abdominal MRI, CT scan, echoendoscopy, with high level insulinemia and metastatic lesions in the liver found on echoendoscopy. Selective celiac artery catheterization shown tumor in second part of duodenum. All tumors were successfully operated. Conclusions: Repeated insulin dosage is necessary to confirm insulinoma as well as multiple imaging methods. Echoendoscopy is still the gold standard for insulinoma detection, CT and MRI are useful in planning the surgery by indicating the exact location regarding the adjacent structures. Background: Due to its cross-talk with estrogen receptor (ER) signalling, increased IGF-I signalling through the IGF-I receptor (IGF-IR) has been postulated as an important factor in the development of tamoxifen resistance in breast canc Continue reading >>

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