Endoscopic ultrasonography--a sensitive tool in the preoperative localization of insulinoma.

Objective: A number of imaging modalities have been used in the preoperative localization of insulinomas. Computed tomography (CT) is the most commonly employed modality. Endoscopic ultrasound (EUS) allows the transducer to be placed in close proximity to the pancreas, thereby yielding higher quality images, which facilitates accurate localization, minimally invasive surgery, and a lower occurrence of residual tumors, all of which contribute to a better clinical outcome.

Methods: We analyzed the hospital records of all adult patients (age >18 years) diagnosed with insulinoma between October 2004 and September 2010. The diagnosis was based on the clinical practice guidelines of the American Endocrine Society. We compared the sensitivities of EUS and multidetector computed tomography (MDCT) in lesion.

Results: Eighteen patients were seen over a period of 6 years, and all underwent EUS. MDCT scans were carried out in 17 patients. EUS had greater sensitivity (89%) in localizing insulinomas compared to CT (69%). In this series, the lesions that were missed on CT but picked up on EUS were smaller (<12 mm, P<.001). Lesions that were near mesenteric vessels and those located in the head of the pancreas were more likely to be missed on CT.

Conclusions: EUS has a greater sensitivity in identifying and localizing insulinomas. As availability increases, EUS should be part of a preoperative insulinoma workup.