Introduction: Various imaging modalities are used in the preoperative localization of insulinoma. CT is the modality that is in widespread use. Endoscopic ultrasound (EUS) allows the transducer to be placed in close proximity to the pancreas, thereby yielding images of higher quality, leading to accurate localization. An accurate preoperative localization results in a minimal invasive surgery and less occurrence of residual tumors, translating into a better clinical outcome. Objective: To assess the sensitivity of Endoscopic ultrasound in the pre-operative localization of Insulinoma, and compare it with that of multidetector CT abdomen.
Methods: We analyzed the hospital records of all adult patients (age > 18 yrs) diagnosed to have insulinoma, over a period of 6 yrs, from Oct 2004 to Sept 2010. The diagnosis was based on the clinical practice guidelines of the Endocrine Society. The sensitivity of EUS was compared with MDCT in localization of the lesion.
Results: Eighteen patients were seen over a period of 6 years, from 2004 to 2010. EUS was carried out in all the 18 patients. Multi-detector CT scans were carried out in 17 patients. EUS had greater sensitivity (89%) in localizing insulinomas in comparison to CT (69%). In this series, the lesions which were missed on CT, but picked up on EUS were smaller (less than 12 mm, P = <0.001). Lesions which were close to the mesenteric vessels and those located in the head of the pancreas were also more likely to be missed on CT.
Conclusion: EUS has greater sensitivity than CT abdomen in picking up and localizing insulinoma preoperatively. With increasing availability, EUS should be part of the preoperative insulinoma workup.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.
The first image shows the lesion in close proximity to the mesenteric vein with which it was confused. The EUS showed a well defined hypoechoic lesion in the uncinate