{"id":8190,"date":"2022-12-21T06:23:25","date_gmt":"2022-12-21T11:23:25","guid":{"rendered":"https:\/\/gastropedia.pub\/en\/?p=8190"},"modified":"2023-12-29T14:01:07","modified_gmt":"2023-12-29T19:01:07","slug":"insulinoma-diagnostic-strategies-and-details-for-treatment","status":"publish","type":[],"link":"https:\/\/gastropedia.pub\/en\/surgery\/insulinoma-diagnostic-strategies-and-details-for-treatment\/","title":{"rendered":"Insulinoma: Diagnostic strategies and details for treatment<\/strong>"},"content":{"rendered":"

Insulinoma is the most frequent functioning pancreatic neuroendocrine tumor (55%), with its peak occurrence in patients in their fifth decade of life (between 40 and 50 years) and a slight predominance among women (1.4:1)1<\/sup>.<\/p>\n

The symptoms associated with the tumor are divided between adrenergic<\/strong> – anxiety, tremors and agitation – and neuroglycopenic<\/strong> such as disorientation, visual alterations and seizures2<\/sup>. Due to frequent food intake to avoid severe hypoglycemia during fasting, it is common for patients to present with obesity\/overweight at diagnosis.<\/p>\n

In 1938, the Whipple triad<\/strong> was described: documented hypoglycemia (<50mg\/dL), symptomatic and relieved after caloric intake. Currently, diagnostic confirmation is given with a clinical fasting test of 48 to 72 hours in which laboratory tests are collected periodically. The laboratory profile will show low blood sugar in opposition to high levels of insulin, pro-insulin and C-peptide3<\/sup>. It is essential for diagnosis to ensure that the patient does not use oral antidiabetics such as sulfonylureas or injectable insulin.<\/p>\n

The relationship of insulinoma in endocrine syndromes<\/strong> (MEN-1 and tuberous sclerosis) is known and brings propaedeutic particularities due to a higher risk of multiple neuroendocrine tumors or malignant insulinomas4<\/sup>.<\/p>\n

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Figure 1<\/strong> \u2013 Caudal pancreatectomy in a patient with MEN-1, the arrows point to the resection of two neuroendocrine tumors.<\/figcaption><\/figure>\n<\/div>\n

The recommended treatment is surgical excision of the tumor. Enucleation, as well as segmental pancreatectomies, are recognized treatments since the vast majority of tumors are benign. Thus, lymphadenectomy becomes less relevant than the preservation of pancreatic parenchyma in order to avoid exocrine or endocrine insufficiency1<\/sup>.<\/p>\n

Therefore, this article aims to bring an analysis of the different diagnostic tests used in insulinoma cases and their applications, in addition to a list of specific perioperative care for these patients.<\/p>\n

Diagnostic methods by image<\/strong><\/h2>\n

Axial methods with contrast are the most used for the anatomical study of the pancreas and its vascular relations. Among them, magnetic resonance, when available, has proven to be more sensitive to locate insulinomas that present as hypervascular nodules in the arterial phase, with hyperintensity in T2 and hypointensity in T1 in relation to the pancreatic parenchyma. Smaller lesions can be located more easily in diffusion phases5<\/sup>.<\/p>\n

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Figure 2<\/strong> \u2013 Magnetic resonance imaging with finding of a hypervascular lesion in the tail of the pancreas, in proximity to the spleen<\/figcaption><\/figure>\n<\/div>\n
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Figure 3<\/strong> \u2013 Abdominal tomography with contrast in the arterial phase with finding of a hypervascular lesion in the body of the pancreas near the superior mesenteric vein.<\/figcaption><\/figure>\n<\/div>\n

A specific exam for neuroendocrine tumors that uses their somatostatin receptors, the PET Gallium 68<\/strong> can assist in cases of clinical suspicion without diagnosis by the methods above. It is an appropriate exam for the location of ectopic insulinomas that were not visualized in the upper abdomen5<\/sup>.<\/p>\n

Invasive diagnostic methods<\/strong><\/h2>\n

Echoendoscopy<\/strong>: Exam for evaluation of the pancreatic parenchyma in search of subcentimetric lesions, used by some authors as the first exam to locate the insulinoma. It offers even greater sensitivity in lesions of the head of the pancreas and uncinate process.<\/p>\n

In the report of a suspected insulinoma, it is important to include, if possible, the measurement of the tumor, its location and the distance from relevant vascular structures (spleno-mesenteric junction), and the proximity of the main pancreatic duct (to assist the operative decision to enucleate the lesion).1<\/sup><\/p>\n

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Figure 4<\/strong> \u2013 Measurement of neuroendocrine tumor by means of echoendoscopy<\/figcaption><\/figure>\n<\/div>\n

Needle puncture is dispensable in the vast majority of cases. The symptomatic patient with sporadic lesion does not need histopathological confirmation for treatment. In endocrine syndromes, both functioning and non-functioning neuroendocrine tumors can express immunohistochemical markers for insulin. Thus, this exam is not suitable to differentiate them. 6<\/sup><\/p>\n

In non-peripheral or intrapancreatic lesions of difficult location, the surgeon may request a tattoo with methylene blue to facilitate intraoperative location.<\/p>\n

Selective pancreatic arterial catheterization (SACS)<\/strong><\/h2>\n

The exam consists of positioning a collector catheter in the right hepatic vein to collect the blood level of insulin after arterial stimuli.<\/p>\n

Then, after selective arterial catheterization, calcium gluconate is injected into the peripancreatic arteries with the power to topograph the lesion if insulinemia doubles within 3 minutes after injection.<\/p>\n