Pre‐ and intraoperative localization of insulinomas: Report of 22 observations

Abstract

From a retrospective analysis of 22 cases of pancreatic insulinoma operated in our center, we have determined the predictive value of various pre‐ and intraoperative localization procedures. In 18 patients, solitary insulinomas were localized by selective arteriography (SA) in 55.5% of cases, by transhepatic catheterization with pancreatic venous sampling (THVS) in 64% of cases, but by ultrasonography (US) and computed tomography (CT) in only 11% of cases. The combination of SA and THVS allowed the preoperative localization of the tumor in 83% of cases. Intraoperative palpation, ultrasonography, and blood glucose monitoring localized a single tumor in all cases. When the insulinomas were multiple, the various preoperative investigations were not reliable. In the 4 cases of multiple insulinoma, various investigations (SA, US, CT, THVS) localized only 8 (28%) tumors of 28. Intraoperative palpation was also unreliable. Only intraoperative ultrasonography and continuous blood glucose monitoring localizeall multiple tumors (the diameter of the smallest tumor was 4 mm). These 2 intraoperative investigations are now the procedures of choice for the detection of small pancreatic insulinomas.

Endoscopic Ultrasonography for the Preoperative Localization of Insulinomas

“…More recently, promising results were reported with selective intraarterial injection of calcium (5) and methylene blue (6). Noninvasive methods (US and CT) have a low sensitivity (0-73%) (2,7-15), whereas invasive methods (angiography, THVS) are more accurate (52400%) but are expensive and time-consuming and require an experienced radiologist (2,9,10,(12)(13)(14)(15)(16)(17)(18). Since the introduction of intraoperative ultrasonography (IOUS) (19), nearly 90% of insulinomas can be localized at surgery in experienced centers, but surgery is still facilitated by preoperative localization (9)(10)(11)(12)(13)17,(20)(21)(22).…”

Modified intra-arterial calcium stimulation with venous sampling test for preoperative localization of insulinomas

“…These inconsistent results have prompted the development of a more sensitive localization method, such as percutaneous portal vein insulin sampling (PVS) [11]. However, this technique requires special skills and experience, which are difficult to achieve because insulinomas are rare, with an incidence of only one to four per 1 million person-years [12][13][14][15]. Reports on dynamic CT and magnetic resonance imaging (MRI) have seemed promising [16][17][18].…”

Value of abdominal sonography and MR imaging at 0.5 T in preoperative detection of pancreatic insulinoma: a comparison with dynamic CT and angiography

“…False-negative diagnoses may occur due to inadequate equipment, incorrect execution, movement artifacts, and poor tumoral vascularization. False-positive diagnoses are also possible [7,31].…”

“…Angiography, however, is thought to be the most effective preoperative method to localize multiple small insulinomas [7,19]. The detection rates reported in the recent literature vary from 41% (18) to 89% (8).…”

“…Filling the stomach with water was seldom used to facilitate exploration of the pancreatic body and tail. Positive criterion for insulinoma detection was the identification of a focal pancreatic lesion, either hypo-, iso-, or hyperechoic [7,8,12,13]. MR imaging was performed with a 0.5-T superconducting magnet.…”