Endosonography in diagnosis of insulinoma

In a prospective study endoscopic ultrasonic localisation of clinically suspected insulinomas was compared with the findings of abdominal ultrasound, computed tomography and magnetic resonance imaging. From Dec. 1990 to Jan. 1995 11 patients (8f, 3m, median age 42 [27-79] years) were enrolled in the study. The preoperative endosonographic findings were compared to surgery (n = 7) or clinical follow-up (n = 4). Endoscopic ultrasound identified a solitary tumour (mean size 12.4 mm) in 7 of 11 patients, which was proven at surgery in 5 patients and by transhepatic portal venous sampling after negative partial pancreas resection in 1 patient. One patient is still awaiting surgery. Clinical follow-up (n = 2) and negative intraoperative and histological findings of partial pancreas resection (n = 1) confirmed a true negative examination in 3 patients. One patient with negative endoscopic ultrasound is still under medication for recurrent hypoglyctemia. Abdominal ultrasound (n = 11), computed tomography (n = 11) and magnetic resonance imaging (n = 5) were negative in all investigated patients. Endoscopic ultrasound is highly accurate for localisation of insulinomas and should be performed early in the preoperative management of these patients.