[Rational preoperative diagnosis of insulinoma]

An insulinoma is the most common pancreatic endocrine tumor. Typical is the presence of a solitary tumor. In 10% of the cases an insulinoma may occur in multiple sites, especially in MEN syndrome. Malignant insulinomas appear in 10% of cases. Insulinomas occur at every age, but mainly about the 50th year. Because of its small size (a diameter of 1-2 cm) diagnostic localization is often difficult. With costly imaging techniques such as CT and MRI, only 60% of the adenomas can be detected preoperatively. If reoperation is a possibility, CT and MRI are advisable. Based on our own experience and the reports of other authors, we advise the combination of transabdominal ultrasound and endosonography for the primary operation. With these methods 90% of the adenomas can be localized preoperatively. If the clinical and biochemical insulinoma diagnosis is definite, explorative laparotomy is indicated even without preoperative morphological tumor detection. With intraoperative ultrasound and systematic palpation more than 97% of insulinomas can be found and resected. We report the case of a 54-year-old woman with unsuccessful preoperative localization in spite of extensive clinical, biochemical and imaging procedures over a 6-month period.