Insulinoma in a patient with annular pancreas.

Intraoperative ultrasonography has facilitated the localization of insulinomas. In this report, we describe a patient who was found to have an insulinoma in association with an annular pancreas. Because such tumors can be in close approximation to major pancreatic ductal structures, intraoperative ultrasonography can be useful for not only localizing the lesion but also delineating the related anatomic features. Although the optimal management of an asymptomatic annular pancreas has not been determined, our patient had no evidence of chronic pancreatitis and no narrowing of the duodenal lumen; therefore, no bowel bypass procedure was done.